Hydroponics, or creating an indoor hydroponic garden, may sound like a futuristic idea but it is not. It is part of hydroculture, the practice of growing plants only using water with a growing medium and nutrients. There is no soil involved.
With the hydroponics technology available today, we can grow our favorite plants, or any plant for that matter, at any time of the year. With the latest hydroponic systems along with specialized horticultural lighting, hydroponics at home becomes easy and effective.
If plants receive the water and nutrients they need at their roots, they can grow exceedingly well without soil. When these plants are food, they can feed the world by producing more and better quality plants than soil-based farming can produce.
If you’d like an overview of hydroponics, types of hydroponic systems, and the history of hydroponics, you can read our introductory hydroponics article. If you just want to start with a compact low-cost indoor hydroponic garden before investing in larger-scale hydroponics activities, see our reviews of affordable indoor hydroponic grow systems.
Hydroponic Gardening Benefits
Saves Your Back
Hydroponically grown plants do not involve raking, hoeing, tilling or other back-breaking work. Because the plants do not grow in the soil there is no weeding, no cutworms or moles that can damage your plants and fewer poisonous pesticides. If you buy a hydroponic pump system with a timer that keeps the plants watered with a nutrient-rich solution, you can even go on vacation for a few weeks and not worry about feeding them regularly. You don’t have to buy hydroponic nutrients ready-mixed, which can be expensive. There is also the option of making your own homemade nutrient solution using fertilizer salts and household ingredients. We teach you how to do that later in this guide.
Hydroponics Works Indoors and Out
Whether you live in an apartment or own a small garden, a hydroponic unit can produce bountiful yields of anything from tomatoes to tulips. You can buy a hydroponic unit that can be put outside on a porch or balcony. The natural sunlight combined with a nutrient-rich water solution will ensure that yields are higher than conventional planting and damage caused by disease and pests is significantly reduced. In winter your plants will continue to flourish in artificial light and can even be grown in a basement. Other indoor hydroponic garden options are kitchen or countertop growing systems.
Hydroponics Produces Higher Yields Faster
Hydroponics can produce many times the yield of soil-grown plants over the same period of time. Their roots do not have to push through the soil to compete for nutrients. Instead, a hydroponic system distributes nutrients evenly to each plant. There is always enough water for the plant and there is greater control over what nutrients the plant receives at varying stages of its development ensuring optimum growth. Unlike soil, the nutrient-rich solution combined with the porous growing aggregate lets air circulate freely ensuring that everything grows faster, ripens more quickly, and produces much higher yields.
Nutritionally Rich and Superior Flavor
Many of the fruits and vegetables are grown and harvested in mass numbers and sold in supermarkets have tough skins to facilitate machine harvesting, sorting, and shipping. They come from seeds chosen for their fast growth and high yields – flavor and nutritional content are secondary concerns. Also, many plants are harvested before they are ripe to ensure a longer shelf life. Quality is sacrificed for quantity. Hydroponic fruits and vegetables have higher nutritional value and superior flavor. While you can buy hydroponic vegetables in the gourmet sections of supermarkets at higher prices you can alternatively grow your own for significantly less.
Food Price Increases
As the price of oil continues to increase so do transportation costs. Depending on where you live it is likely that most of your fruit and vegetables are transported long distances before it reaches the supermarket, adding significantly to the cost. Also as agricultural land around the world disappears and is replaced by urban towns and cities and as grower’s costs keep rising, this will further add to the price of food. With supermarkets more concerned about their profit margins, food prices are set to skyrocket in the future. It is not surprising that growing plants hydroponically has become increasingly popular among gardeners. Home hydroponics systems are ideal for those who have limited space which is why they can even be found inside nuclear submarines, space stations and on offshore drilling rigs. Hydroponics will not lead to high water costs as the water stays in the system and can be reused – another advantage of hydroponics over soil-based gardening.
Hydroponic Grow Systems
There are a variety of techniques used in hydroponic gardening. The most common techniques are called deep water culture or nutrient film technique.
Deep Water Culture
This technique suspends a plant’s roots in an oxygenated, nutrient rich water solution. A growing medium, like small stones, Perlite or Vermiculite is used to support the roots instead of using soil. This system is also sometimes called bubbleponics because air pumps are using to oxygen the water using bubbles.
Nutrient Film Technique (NFT)
The Nutrient Film Technique is another popular hydroponic grow system where a stream of nutrient rich water is periodically flowed through a plant’s roots using some form of water channel.
Alternative Hydroponics Grow Systems
There are several variations of hydroponics systems that you may encounter. The following are the most common. Also, note that soil-based systems are sometimes referred to as geoponics.
An aquaponics system uses aquatic animals (fish, snails, etc.) to provide organic hydroponic nutrients in their waste to the growing plants. The plants then help with cleaning the water and creates a symbiotic plant/animal ecosystem. Often, these aquaponic growing systems combine a hydroponic aquarium or fish tank. The smaller systems provide a great educational tool for students.
Aeroponics systems grow plants in an air or mist environment, rather than having the roots submerged in water.
Anthroponics is a form of organic hydroponics that uses human waste, such as urine, as the source of hydroponic nutrient solutions. The solutions are passed through a biofilter before being applied to the plants. The plants absorb the nutrients, which further cleans the water.
This form of hydroponics specializes in systems using coco (coconut) peat as the growing medium.
Hydroponic Growing Mediums
A good hydroponic growing medium has the following properties:
- Should be able to stay pH-neutral and buffer pH changes
- Hold nearly equal concentrations of air and water
- Able to hydrate and re-hydrate quickly
- Can be recycled/reused and is biodegradable
- Cheap and easy to obtain
- Lightweight and easy to move around both outdoors and indoors
The best hydroponic medium also depends on the type of hydroponic system you will use. The most commonly used mediums for hydroponics are coconut coir, agricultural grade perlite, expanded clay pellets, Rockwool and common pea gravel. Other less common growing mediums include composted bark, gravel, oasis, peat moss, pumice, sand, sawdust, soilless mix(s), vermiculite and gravel. You can mix mediums together. For example, coco coir is often mixed with 50/50 perlite to provide a higher air holding ratio than coconut coir alone.
A popular growing medium is coconut coir, otherwise known as coconut fiber. Coconut coir combines the air retention of perlite, with the water retention of vermiculite and it is a completely organic medium. It can be reused and is biodegradable, relatively cheap and easy to obtain. It is also lightweight and easy to work with. Another benefit of using coconut coir as a growing medium is that it offers plants protection against fungus and root diseases due to its anti-fungal properties. For all of these reasons, coconut coir is becoming one of the most popular growing mediums amongst hydroponic gardeners.
The advantage of perlite is that it has excellent oxygen retention and is very lightweight making it easy to transport. It mixes well with other growing mediums. For example, it can be mixed with soil and soil-free mixes to provide greater oxygenation for the plant roots. While its lightweight properties make it easy to transport and apply, a disadvantage is that it can get washed away in some hydroponic systems (the Ebb and Flow system, for example). However, it works well with the wick-type hydroponic systems as perlite has good wicking action.
Expanded Clay Pellets
Lightweight Expanded Clay Aggregate (LECA) is a very loose medium with large grains. The advantage of expanded clay pellets is that they remain pH-neutral and are reusable. This makes them cheaper and friendly to the environment. The advantage of clay pellets is the shape and internal structure of the pebbles which ensures good root aeration and drainage and helps prevent rotting. The disadvantage is that expanded clay pellets are dusty, so they will need to be rinsed thoroughly before going into your hydroponic system.
Rockwool is made from molten rock that has been spun into long, glass-like fibers. Rockwool is usually sold as cubs or in a loose form. rockwool is used in wall insulation and is popular amongst the commercial greenhouse industry. The advantage of Rockwool is that it can be used for a wide variety of hydroponic systems, it easily absorbs water and drains well. It’s also completely sterile and non-toxic and makes for a good starting medium for seeds, cuttings, and small immature plants. If your system constantly recirculates your nutrient solution, a fast draining medium such as Rockwool is ideal. The disadvantage of Rockwool is that it is not biodegradable. Also, gardeners have complained of the substance irritating their skin.
Common Pea Gravel
Pea gravel is made up of stones less than an inch in size. Like expanded clay pellets they remain pH-neutral and are reusable. Unlike expanded clay pellets, they are heavier. This can make transportation more difficult. The advantage of using a heavy grow medium is that the medium does not get washed away with Ebb and Flow type systems.
Hydroponic Nutrient Solutions
Introduction to Hydroponic Nutrient Solutions
Unless you are an experienced hydroponic gardener, we recommend that you buy hydroponic nutrients ready-made/ready-mixed rather than make your own homemade hydroponic nutrient solution.
Many gardeners don’t want to go to the bother of making their own hydroponic nutrients, and pre-mixed hydroponic nutrients usually provide a balanced diet while allowing you to concentrate on other aspects of plant care. Also, you may wish to adjust your nutrient solution later depending on the stage of development and conditions of the plants; ready-made hydroponic nutrients are more manageable and the nutrient concentrations are easily identifiable.
You can find hydroponic nutrients for sale at many large nurseries and hydroponics stores. These usually contain all the essential nutrients and trace elements. However, if you want to give your plants an extra boost, the best hydroponic nutrient brands provide nutrient solutions containing not only the essential macro and microelements but crop enhancers such as root boosters, amino acids, microbes, enzymes, vitamins, F-1 (fulvates), H-2 (humates) and a non-ionic surfactant.
Choosing between brands can be confusing and it can be expensive and time-consuming to do comparison testing. Based on our experience, these exotic nutrient solutions can make a significant difference to yields. While there may not be a significant difference between manufacturers, you should avoid lesser-known hydroponic nutrient suppliers as many of these “hydroponic manufacturers” don’t actually make all of their own products and sometimes a very different product is sold to you because they switched suppliers. This can be detrimental to your plants.
The best hydroponic nutrients will depend on many factors and there are many variables that need to be controlled to carry out a successful comparison. To discover the best hydroponic nutrients for your plants you should do your own experiments, perhaps setting aside a few of your plants specifically for that purpose and placing them within the same environment to ensure accurate test result.
Commercial Nutrient Solution Providers
General Hydroponics – Hydroponic cultivation by NASA on the International Space Station is done with assistance from General Hydroponics. They claim to be at the cutting edge of scientific research into hydroponic systems and perfecting nutrient formulas.
Advanced Nutrients – Advanced Nutrients provide 2-in-1 and even 5-in-1 solutions that contain base nutrients with added ratios of chelated macro and microelements, crop enhancers such as humates, fulvates, amino acids, and a non-ionic surfactant. They have a large selection of solutions and formulas to suit your skill level and needs. They also claim to have developed the first-ever pH-perfect nutrients.
Botanicare – Botanicare started developing experimental plant nutrients in 1992 and since then has grown into a leading nutrient provider. They provide an online nutrient calculator that could be useful for your hydroponics activities.
CANNA – A Dutch company, CANNA products with a wide range of high-quality gardening fertilizers and plant nutrients.
Fox Farm – This company is a family business dedicated to producing the finest quality garden products available anywhere. Their soil mixes, soil conditioners, and fertilizers are specially formulated to replenish the soil.
Technaflora – This is a Canadian company offering a variety of nutrients and additives for hydroponics and specialty gardening.
Dutch Masters – This is a family-owned brand of plant fertilizers, originally from Australia but now global, that specializes in optimal nutrition for cannabis plants.
DIY Hydroponic Nutrient Solutions
If you don’t want to buy hydroponic nutrients ready-made and you believe you’re experienced enough to create your own hydroponic homemade nutrients, we recommend you use fertilizer salts. These are the most common type of homemade hydroponic nutrients and are very rudimentary and cheap, assuming you can buy them in small quantities. You can buy them in bulk from plant food suppliers, plant nurseries, and agricultural agencies. Unfortunately, if you buy hydroponic fertilizer salts from these suppliers you often have to buy in twenty-five to fifty-pound bags, which isn’t practical or cost effective unless you are buying for a large-scale commercial business or an extensive hydroponic garden. We recommend instead you buy fertilizer salts from online sites such as Amazon as these suppliers sell them in smaller quantities.
Here is a list of recommended fertilizer salts for those who want to make their own hydroponic homemade nutrient solution.
|Salt||What it supplies…|
|Magnesium sulfate (Epsom salts)||Magnesium and Sulphur|
|Potassium sulfate||Potassium and Sulphur|
|Potassium nitrate||Nitrogen and Potassium|
|Superphosphate||Phosphorus and Calcium|
|Calcium sulfate||Calcium and Sulphur|
|Ammonium phosphate||Nitrogen and Phosphorus|
The following is a workable, tried and tested hydroponic homemade nutrient solution. There are many different nutrient formulas, but as long as the elements are present in balanced amounts the plant should be fine – it will extract from the solution what it requires. Of course, every plant is different and exists in different conditions. You should experiment with what works best for you.
The recommended quantity is the weight in ounces that experts recommend in a 100 Imperial (120 American) gallon water solution.
Homemade Hydroponic Nutrient Solution
|Ammonium sulphate||1.5 ounces|
|Potassium nitrate||9 ounces|
|Monocalcium phosphate||4 ounces|
|Magnesium sulfate||6 ounces|
|Calcium sulfate||7 ounces|
|Combine with trace elements and 100 gallons (120 American gallons) of water, or 1 ounce per 3.7 Imperial gallons.|
In addition to the three key elements of nitrogen, phosphorus, and potassium there should be at least 8 trace elements present in your nutrient. These include zinc, copper, sulfur, manganese, iron, calcium, magnesium and boron, chlorine and molybdenum. Chlorine and molybdenum are already present in either the water supply or salts mentioned above and therefore should not be added to avoid toxicity.
Function of each element in a hydroponic solution:
|Nitrogen||Necessary for the production of leaves and in stem growth. An essential ingredient in building plant cells.|
|Phosphorus||Required in the development of flowers and fruits and aids in the growth of healthy roots.|
|Potassium||Used by plant cells during the assimilation of the energy produced by photosynthesis.|
|Sulfur||Assists in the production of plant energy and heightens the effectiveness of phosphorus.|
|Iron||Vital in the production of chlorophyll. Manganese aids in the absorption of nitrogen. An essential component of the energy transference process.|
|Zinc||An essential component in the energy transference process. Copper needed in the production of chlorophyll.|
|Boron||Required in minute amounts, but it is not yet known how the plant uses it.|
|Magnesium||One of the components of chlorophyll, magnesium also is involved in the process of distributing phosphorus throughout the plant.|
|Calcium||Encourages root growth and helps the plant absorb potassium.ChlorineRequired for photosynthesis|
|Molybdenum||Assists in some chemical reactions.|
The trace elements that are added to these formulas must be mixed separately. One recipe is given below. You can use a mortar and pestle to grind to a very fine powder.
Trace elements Solution
|Zinc sulfate||½ teaspoon|
|Copper sulfate||½ teaspoon|
|Iron sulfate||1 ounce|
|Manganese sulfate||1 teaspoon|
|Boric acid powder||1 teaspoon|
These ingredients should be ground well and stored dry. You should use half a teaspoon per 100 gallons or 120 American gallons of water.
Hydroponic Grow Lights
The best hydroponic grow light for you will depend on a number of factors. These include the cost of the light, the energy cost of running the light x number of hours a day. The environment that the plant is in and what stage of growth you are trying to facilitate.
Fluorescent and Incandescent grow lights
While they are cheap to buy they are rather inefficient as hydroponic grow lights. Incandescent and fluorescent grow lights are fine for low-light plants where limited results are expected. However, the light is of a low intensity and they produce a low level of lumens per watt and are therefore less efficient than High-Intensity Discharge lights (HID) or Light Emitting Diode (LED) grow lights. Incandescent lights have a much shorter usable bulb life than high-pressure sodium lights and LED grow lights. They also have approximately six times lower light output per watt of energy consumed than a High Pressure Sodium (HPS) light.
High Intensity Discharge Lighting (HID)
High Intensity Discharge lighting consists of a lamp, reflector and power supply. They are designed to produce a high output of photosynthetically active radiation (PAR) for the amount of power consumed. It is not just the quality of the light but the quantity that is also important and High intensity discharge lights can produce both.
Commercial growers and some of the world’s premier growers use High-Intensity Discharge lights and produce impressive results that would be impossible with conventional fluorescent and incandescent lamps.
Until recently High-Intensity Discharge lighting for horticulture has not been cost-effective. As a result of new lighting products by manufacturers like Hydrofarm and Sunlight Supply, lighting costs have been significantly reduced making the use of such lights profitable.
High Intensity Discharge lights are designed to cover the PAR spectrum (Photosynthetically Active Radiation). The wavelengths of light most important for photosynthesis to occur are the red and blue light spectrum, red being 600 – 680 nm and blue being 380-380 nm. These wavelengths are considered the most important for photosynthesis and HID lights cover these spectrums well.
There are two types of HID lamps which emit different color spectrums:
Metal Halide (MH) Grow Lamps
Metal halide lamps emit light at the white/blue spectrum. Metal Halide lamps are best used as a primary light source if there are no other light sources and little or no natural sunlight is available. They consume large amounts of energy but produce significant quantities of light.
Advantages of Metal Halide Lamps:
- Best when there are no other light sources
- Promotes compact vegetative growth
- Best for vegetative growth
- Emit high levels of blue light promoting growth of leafy plants
High Pressure Sodium (HPS) Grow Lamps
High-pressure sodium grow lights have a long usable bulb life and are a much more efficient means of producing light than standard incandescent grow lights. They emit a yellow/orange spectrum of light and have a yellowish glow. They are good when used in combination with other light sources such as weak sunlight during the winter months.
Advantages of High Pressure Sodium Lamps:
- Work well with other light sources (natural sunlight etc)
- Best for flowering/budding stages of growth
- Ideal for a hydroponic greenhouse or commercial growing application
- Emit high levels of red light good for flowering and fruiting plants
The Hortilux HPS lamps add an additional 30% blue factor to their spectrum making them more efficient than other HPS lamps for solo use.
You can also buy High-Pressure Sodium to Metal Halide conversion bulbs. These can switch from emitting Metal Halide light during vegetative growth then let you switch back to High-Pressure Sodium for the flowering/budding stage of growth.
LED Lights for Hydroponic Gardens
What are LED Lights?
LED grow lights are the most efficient means of producing light for plant growth as the light produced is specifically designed to target narrow wavelengths required for photosynthesis also most of the energy is not lost in the form of heat like other grow lights. LED grow lights have the highest PAR value (photosynthetically active radiation) of all grow lights. The downside of LED grow-lights is that they are expensive to buy and while being the most efficient, the cheaper models don’t produce enough lumens to be effective for growing a decent size crop.
LED lights are just small light bulbs that can fit easily into an electrical circuit but unlike ordinary incandescent bulbs, they don’t have a filament that burns out, and they don’t get very hot. This means they last a lot longer. They can also be configured to emit light at specific wavelengths thereby making them more efficient for growing plants which require light between 400 to 700 nanometers.
Advantages of LED Grow Lights:
- Produce less heat than other light sources which can damage plant and dry up the hydroponic solution
- Much longer bulb life than other lamps. Typical lifetimes quoted are 25,000 to 100,000 hours
- Lower energy costs due to higher efficiency
- No costly cooling system required unlike Halide Lights which get hot
- LED grow lights do not contain the harmful mercury-filled bulbs that exist in some other grow lights
- Powerful LED grow lights have been shown to produce higher yields and vegetative growth
Efficient Means of Producing Light
Thanks to new technology LED grow lights have become the most efficient means of producing artificial light for plant growth. This is because LED grow-lights have a high photosynthetic photon flux (area) density for every Watt consumed. What does this mean?
Photosynthetically Active Radiation
According to Wikipedia “Photosynthetically active radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers(nm) that photosynthetic organisms are able to use in the process of photosynthesis”.
Photosynthetic Photon Flux Density (PPFD) refers to the photosynthetically active radiation emitted per square meter per second. In other words, it is how much energy suitable for plant growth emitted every second for every square meter of plant. The higher the PPFD the higher the crop yield as the light can cover a larger area.
Plants only require light energy within a narrow frequency of between 400 and 700 nanometers (nm’s) and other frequencies can even be harmful to a plant. A frequency too high can damage the cells and a frequency too low won’t penetrate the plant.
Because hydroponic LED grow lights can be manufactured to emit light at narrow wavelengths specifically suited to plant growth they are more efficient and don’t require as many watts to run as other grow lights.
How to Measure Efficiency
The efficiency of a LED grow-light is determined by PPFD per watt of energy. The PPFD per watt will determine how efficient a light source is at producing photosynthetic active radiation per watt of power.
The efficiency of an LED grow-light can be expressed as the number of grams of crop produced per watt. However, this will vary depending on the plant and other environmental factors.
Since the photosynthetically active radiation range occurs within the visible spectrum it is common for the brightness of the light to be measured in lumens or lux.
If these lights are left on 24 hours a day and use a high wattage they can still run up your energy costs. You want a powerful LED grow-light that produces a high plant yield but efficient enough that it consumes a relatively low wattage.
Hydroponic Air Pumps
What are Hydroponic Air Pumps?
Hydroponic air pumps are used to pump air into a hydroponic nutrient reservoir. Air stones which are inside your hydro tub and connected by an air-line tube to your air pump convert the air into small bubbles. This produces oxygen inside your nutrient reservoir which is absorbed into the nutrient solution and utilized by the roots.
Plant root systems require water, nutrients, and oxygen. Aerating the roots improves nutrient update and water absorption increases cell growth and activity. Increased oxygen to the root system has been scientifically proven to increase crop yields. Aerating the water also prevents the nutrient solution from becoming stagnant which can lead to root rot and other problems.
Hydroponic air pumps are a cheap and effective way to provide oxygen to your plants. All you need is an air pump, air stones and an air-line to connect the air stones to the air pump.
Buying a Hydroponic Air Pump
When choosing a hydroponic air pump, a regular air pump designed for an aquarium is all that is required. There are many brands to choose from. Some air pumps are built specifically for hydroponics, almost all are built for aquariums but they all do much the same thing – they produce air which is then converted into bubbles to oxygenate the water in an aquarium or hydroponic reservoir.
When buying a hydroponic air pump there are a number of factors to consider and specifications listed by the manufacturer. These include:
Open flow or maximum capacity is the maximum flow of air produced without any restriction on the air being drawn by the pump. The Open flow is usually measured in liters or gallons per minute or hour. The amount of air that can be pumped into a hydroponic reservoir is affected by airflow resistance or drag. The air flow or drag is affected by the length of the tubing and depth and pressure of the solution. The greater the PSI of an air pump, the more freely the air will flow.
PSI (Pounds per Square Inch)
The PSI of the air pump is sometimes given. The higher the pressure the lower the drag. A higher PSI means the air will flow more freely through the tubing into the reservoir.
Noise Level measured in Decibel (dB). Some less efficient air pumps are noisy. This can be a nuisance with indoor hydroponic growing systems. Air pumps produced by Secoh – a Japanese company, are said to be almost silent in operation as well as reliable, efficient and high quality.
Maximum electrical power consumption is usually measured in watts. The higher the power, the greater the airflow. While some brands and devices are more efficient than others, a general rule-of-thumb is 1 watt for every gallon of nutrient solution.
Usually measured in hours, this is the estimated time that the device will maintain the specifications given. You can improve life expectancy by replacing parts that get worn or damaged (see below).
Number of Outlets/valves
The number of outlets on an air pump will determine how many air stones and air-line tubing’s you can connect to the air pump. This is useful if you have your plants situated in a number of different buckets or barrels and need an air stone in each container. Some air pumps can have as many as 12 outlets.
Air pump tubing size is the inner diameter of the tubing which is connected to the air pump vales – usually measured in inches or centimeters.
The price of an air pump will depend on the brand, wattage, materials, and accessories that come with the air pump. You don’t have to spend much on a hydroponic air pump. You can buy a cheap air pump for around $20 – $45 that would be suitable for most indoor hydroponic systems.
Another factor to consider is whether the air pump is rainproof. If you’re intending to use the air pump outside, a rainproof enclosure will protect the air pump from rain or splashes of water.
What is the Best Air Pump Brand?
The following air pump manufacturers produce air pumps that can be used for both aquariums or hydroponic systems: Rena, Hiblow, Secoh, Alita, Koi, Medo, EcoPlus, Hakko, General Hydroponics, and Danner.
- General hydroponics – they produce the dual diaphragm air pumps boast that they are the only brand that specifically builds air pumps for hydroponic systems. However, any aquarium pump can be used in a hydroponic system.
- Secoh Septic – a Japanese company, is said to be almost silent in operation as well as one of the most energy efficient hydroponic pumps, it is both reliable, and of a high quality. They claim to have won the best pump in just about every independent review. However, because it is a foreign company finding spare parts that need replacing may be more difficult. They can also be pricey.
- Eco Air – This pump is considered quiet, efficient and long lasting with a controllable variable output on some models. They also operate without the need for oil.
Air Pump Accessories
Air stones come in different shapes and sizes with the most common being golf ball or cylindrical-shaped. They are designed to convert air from the hydroponic pump into a gentle flow of bubbles that rise to the surface. Oxygen is essential to plant. These air bubbles are absorbed into the nutrient solution and used by the plant roots.
Micro-pore diffusers are similar but superior to air stones because they are designed to produce a larger quantity of smaller more prolific bubbles over a larger area. They tend to be more long-lasting than air stones and do not clog up so easily. They are made of kiln-fired ceramic material designed to not react with nutrient solutions. You can buy single or double micro-pore diffusers.
Air dividers or port manifolds can be connected to an air pump to create multiple outlets for several air stones or diffusers and therefore provide much greater spread.
Similar to air dividers or port manifolds, they are used for adding an additional line to an existing air-line, or making two outlets from one pump outlet.
Often made of clear silicon air-line tubing fits your pump or manifold and allows air to flow through easily to the air stone or micro-pore diffuser. You should use the same length of line to each stone for equal delivery of air into the water.
Air Pump Maintenance
Air pumps require regular maintenance every few months. This can involve replacing diaphragms and filters to keep them running. You should buy an air pump from a manufacturer that you can easily obtain spare parts from. The Tetra Whisper AP300 is one of the best hydroponic air pumps on the market and a replacement kit should only cost a few dollars and are readily available.
Make sure you have a non-return valve in the air-line to stop the water siphoning back up the air pump and destroying it. This can happen when the pump is positioned below the reservoir.
You should replace valve blocks when the pressure fails or when the pump is functioning less efficiently. These valves do wear out over time and this can result in air leads and lower efficiency. You can lengthen the life of these valves by changing your pump’s air filter monthly.
These filters are usually round and mounted to the bottom of some air pump models. They should be replaced when dirty to avoid damage to the air pump valves and to reduce the chances of the diffusers becoming clogged up.
Over time there will be a buildup of salts from your nutrients, these can clog up your air stones. However, you should be able to remove the clocked materials using a soft toothbrush.
Hydroponic Garden Ventilation
Why is Ventilation Necessary?
To maintain adequate grow room ventilation, grow room fans can be used to control humidity, temperature, and carbon dioxide levels. A grow room fan or hydro fan within a grow room is essential for a number of reasons. By exchanging, circulating and mixing the air, a hydro fan will give you more control over the following:
Inadequate ventilation can lead to high humidity and this can result in a number of problems for the plant at various stages of growth. A humidity of 60% RH (Relative humidity) is recommended during vegetative growth and around 40% RH during flowering to prevent flowers or fruits from rotting. It will also help to prevent fungal diseases as fungal spores thrive in humid, stagnant air. Stale stagnant air also provides other airborne pests such as sciarid flies a greater opportunity to infest your grow room. Hot air holds more water vapor so by extracting hot and humid air and replacing it with cooler less humid air, high humidity will become less of an issue.
Plants need carbon dioxide (CO2) to grow and photosynthesize – this is essential for plant growth. Plants within any confined space will soon use up that carbon dioxide. A hydroponic extraction fan is, therefore, necessary to maintain high levels of carbon dioxide and ensure a fresh supply of air into the grow room. It is recommended that you should try to replace the air in your grow room at least 20 times per hour or every 3 minutes to maintain a reasonable air quality.
Hydroponic lights within a grow room can produce a lot of heat. When the lights are on the temperature should range between 21 to 28 degrees centigrade (70 to 82 Fahrenheit). Try and reduce this temperature by about 5 degrees Celsius (9 degrees Fahrenheit) at night as this is important for correct flower maturation. Grow room ventilation using a hydro fan will help maintain the correct temperature. A hydroponic fan speed controller will enable greater control of the temperature as they can be controlled by a thermostat. A fan speed controller linked to a thermostat will enable you to vary the speed of the hydroponic fan automatically depending on your preferred air temperature.
Good ventilation is essential for healthy plant growth. It is one of the most important factors to consider when growing plants within an enclosed space. Ventilating a grow room or grow tent involves selecting the correct size exhaust fan or extractor fan and maintaining a fresh supply of air from outside. This section of our guide is designed to help you choose the correct hydroponic fan for your grow room, the best setup and recommended method for installing a hydroponic fan.
What Size Fan Should I Buy?
Buying an adequate sized fan for your grow area is important as the cost of a hydroponic fan will largely depend on its size and power. Generally speaking the longer the length of the fan the greater the volume of air that can be extracted at any given minute. However, fan designs can vary significantly and you will want to know the Cubic Feet per Minute (CFM) value of the fan. The CFM specification is the volume of air in cubic feet that can be extracted every minute.
Firstly calculate the area of your grow room or grow tent. Multiply the room’s length by the width by the height. So for example for a 7 foot by 6 foot by 10-foot area, the volume would be 7 x 6 x 10 = 420.
The extraction fan/exhaust fan should exchange the air in the room at least once every three minutes. So simply divide the area in cubic feet by three minutes to calculate the minimum CFM: 420 / 3 = 140 CFM
If you plan to use a carbon air filter (more on that later) multiply by 30%: 140 x 1.3 = 182 CFM.
This is minimum recommended air flow rate and once this has been established you should buy a hydroponic fan with a similar air flow rate. The grow room must include a vent hole to draw air into the room while the hydroponic extractor fan is drawing air out. The vent hole needs to be at least the same size as the size of the extractor. So for example, if you are using a 7-inch extractor then the size of the inlet hole should be at least 7 inches but preferably slightly larger to reduce drag. Also, air drawn in through the inlet hole needs to be near to the ground were as the extractor fan drawing air out needs to be positioned near the top of the grow room or tent. This will enable better air circulation and mixing and also remove the hot air that tends to rise.
An Intake Fan Plus Extractor Fan
An intake fan can be used in conjunction with an extraction fan to pull air out. An intake fan is the same as an extraction fan but is used to pull air into a grow room instead of removing air. Whether you use an inlet hole or an intake fan, the important thing to remember is that fresh air must be drawn in from outside and the extractor fan should be positioned at the top and preferably on the opposite side of the intake fan. If you chose to use an intake fan and an extractor fan, the combined CFM of both fans must total the CFM required. So if you require 182 CFM, one fan could be 140 and the other 42. However, the intake fan should always have a lower CFM and preferably a third to a half of the extractor fan.
Having two fans working together provides better control of humidity and temperature; it creates negative air pressure within the room and prevents smells from escaping back through the ventilation system. You will also discover that the fans will be less noisy and last longer.
If you have to move air to an exterior vent or move air a distance from an outside wall, you may need to use ducting. Ducting comes in standard sizes that should fit all of your fans and filters. Flexible ducting is easier to work with, but it is important to try and keep it straight. Your ducting should be as short and straight as possible. You should try and avoid bends in the ducting as these will create drag that in turn creates noise as the air moves through. It will also lower the efficiency of the grow room fans and may require more powerful fans to compensate.
Buying a Carbon Filter
If the exhaust from your grow room smells you can do something about it. A hydroponic carbon filter can be fitted to your grow room extractor fan. Carbon filters otherwise known as carbon scrubbers will remove almost 100% of the odor from the air before it is extracted. Carbon filters need to be replaced or refilled once in a while.
Normally you would have the following setup: The fan and filter are placed inside the grow room or grow tent and air is drawn through the filter and then the fan before leaving through some ducting to the outside. If the growing area is too small you can get away with having the fan and filter placed outside freeing up space inside the grow room. This way stale air is pulled out of the grow room through some ducting by the fan located outside, the air then moves through the fan, through more ducting and then through the filter before being extracted.
Fan speed controller: A fan speed controller controls the speed of the fan. If the fan speed controller uses a thermostat it can monitor and regulate the temperature of the grow area depending on the temperature. This is more efficient, reduces noise and prevents the temperature and humidity from being too high or low.
Acoustic ducting: If the fans are too loud you can use acoustic ducting to reduce the noise of your fans generated by air turbulence. Fix a silencer on each end of your fan to get the full benefits.
Hydroponic Grow Tents and Grow Boxes
Advantages of Using a Hydroponic Grow Tent or Box
The plants are in a more confined area and as a result, it is easier to control environmental conditions – such as the temperature, humidity, CO2 levels. This makes it easier to create the optimum conditions required for a specific plant.
If you purchase a grow tent with a reflective silver coating the light and heat is reflected off the interior sides and is mirrored back onto the plant leaves. The confined area and reflective surface save energy and money.
Grow tents are easy to set up — such as lighting, ventilation, etc. Lights may be hung from the steel-enforced ceiling, and most grow tents also come equipped with ventilation holes so setting up ventilation is an easy process.
With a grow tent there are fewer problems with pests because there is a barrier between the plants and the outside environment.
Hydroponic grow boxes have similar advantages to a grow tent. However, they tend to be better sealed from the elements and are used for smaller numbers of plants. Another advantage is that they often include integrated features, like a reservoir, tubing and trays and lighting.
Making Money with a Hydroponic Grow Tent
Because its possible to control and fine-tune the environment within a grow tent you can obtain larger crop sizes and healthier plants than most other environments. A hydroponic grow tent enables you to grow exotic and expensive herbs, fruit or vegetables out of season or under conditions that would normally require a different climate. These plants can be sold yourself or you could always sell them onto restaurants, hotels, farm shops, food halls or private buyers at premium prices.
What to Consider when Buying a Grow Tent
When buying a grow tent the 3 most important factors will be the cost, dimensions, and materials. The materials and size of the grow tent are the biggest factors in determining the price. Other Important factors include light and heat leakage, the strength of the frame, user-friendliness, and accessories.
Size and Cost
Indoor grow tents are available in a variety of sizes. Grow tent sizes include the smaller 3×3 and 2×4 foot tents, medium-sized 4×4, 4×6, or 4×8 foot, as well as the larger 5×5 and 10×10 foot grow tents.
The cost of a grow tent can vary significantly but you can buy a grow tent suitable for a hobbyist for between $100 to $200. For this price, you can expect a decent sized grow tent (at least 4ft x 4ft width x 6ft height) with reflective inner lining.
You want a grow tent that is easy to set up with clear easy to follow instructions. Most grow tents are easy to set up.
Grow Tent Accessories
If buying a grow tent you should also purchase a grow light. A high intensity discharge lamp should be used for this purchase as these are powerful enough to mimic natural sunlight while efficient enough to be cost-effective. Other accessories could include the following:
- An Air Duct Inline Hydroponic Booster Fan
- A Flexible Ducting pipe for the air
- A Hydroponic Carbon Air Filter
- An indoor humidity monitor
- A grow light hanger
You can also buy grow tent kits that include all necessary accessories as a single package.
When buying a grow tent you should ensure the following standards are met:
- The inner surface should be made of reflective material to retain light and heat (Mylar reflective inner surface etc)
- Be sturdy and strong enough to be moved around and hold a decent sized grow light and/or fan on the bars above the plants.
- Provide good insulation against heat loss.
- Made of non-toxic, non-flammable materials.
- Easy to set up (user-friendliness)
If you are interested in creating a DIY grow tent, you’ll be interested in the following video:
Hydroponic foggers are devices used in hydroponic or hydroponic/aeroponic hybrid systems to feed nutrients to plant roots via a nutrient fog. A hydroponic fogger differs from an aeroponic mister as the fog is produced ultrasonically and the solution is not atomized.
A hydroponic fogger sits below the water level producing fog, thereby raising the humidity in the rooting zone. If the water particles produced by this fog are small enough – usually between 5-15 micrometers this allows for increased nutrient uptake. The oxygen-rich mist combined with the high humidity and small water particles lead to accelerated growth.
Other Fogger Benefits:
- Reduced need for water and nutrients
- No growing mediums required
- Increase in the overall root surface area due to increased growth of small root hairs
- Reduces the risk of harming the plants with excess nutrients
Things to consider:
- Use only products which do not contain live microbial cultures as hydroponic foggers can sterilize live cultures.
- The disks will need to be cleaned every once in a while. You can use white vinegar for this. Simply place the Hydroponic Fogger in a glass of white vinegar and run the device for a minute or so and the mineral deposits from the nutrients will shed off.
- Replace the Teflon disks every 6 months to a year as the discs wear and the mist output decreases.
- Foggers can increase the temperature of your nutrient solution so monitor the temperature of the solution. A continuous flow of solution such as the ebb and flow system can help keep temperatures down.
- You should consider a hybrid system that includes an ultrasonic fogger used in conjunction with a solution (ebb and flow nutrient film technique, or deep water culture etc) as hydroponic foggers can sometimes fail. The nutrient solution will feed the bottom half of the roots and the upper half of the roots are fed by the fog produced by the hydroponic fogger. Should the fogger fail there is still a system in place to feed the roots nutrients and water. This also leads to maximum oxygenation and access to an unlimited supply of nutrient solution at the bottom of the tray.
- The nebulizers on hydroponic foggers can be damaged quickly if water levels drop too low.
Hydroponic Garden Kits
There are a number of different hydroponic kits and accessories used for different purposes; these can include hydroponic kits built for cloning seeds or cuttings, outdoor and indoor hydroponic kits, hydroponic starter kits, hydroponic tent kits, and others just for supporting your plant in a nutrient solution outdoors.
However the more you substitute for nature, the more complicated these kits are and the more expensive they become. When plants are removed from their natural environment, as in indoor gardening, then all aspects of that environment have to be duplicated by artificial or technical means. The right hydroponic kit will depend on the stage of development, the conditions the plants are grown in and your available budget. Here are some hydroponic kits you may find indispensable:
Hydroponic Cloning Kits
Hydroponic cloning kits can cost between $30.00 to $100.00 depending on the level of sophistication. A hydroponic cloning kit enables you to have faster growth cycles and harvest more often.
The best hydroponic cloning kits will support dozens of trimmings and deliver a high success rate of clones. The cloning kit should consist of a reservoir that holds the water and nutrient solution mix. The growing chamber section usually consists of trays or pots containing a growing medium for root support such as compressed peat or a perlite Vermiculite mix to support the seeds or clippings. An automated hydroponic cloning unit will contain an air pump and watering system that can include a water pump, water spray or mister. You should avoid humidity domes as these can lead to mold and wilting of the plant. Other important components of the kit can include:
- A hormone to enhance the development of roots.
- Hormone rooting compounds such as Rootex-L, Clonex, or Eziroot
- A heating pad or propagation mat
- An anti-stress agent such as superthrive
- Nutrient solution and thermometer
- Pruning shears or sharp scissors
You should see tiny root bumps appearing after 3 days and in about a week these roots should be formed and expanding. After about 2 weeks the plants should be ready to be transported into whatever medium you wish – this could be soil or a hydroponic unit.
Hydroponic Grow Kits
When your plants have matured to a size that cannot be supported by the cloning kit they can be transported to a hydroponic grow kit. Much of the components required are similar to that of the cloning kit except the unit will be on a larger scale and may be housed within a tent.
A hydroponic grow kit will require light either from the sun or a powerful LED grow light and different nutrients depending on the stage of development.
The cost of a hydroponic grow kit can vary significantly in price from hundreds to thousands of dollars depending on the size and type of hydroponic unit, however, you can find some inexpensive hydroponic kits for sale on Amazon for less. There are a number of different hydroponic units available to growers and hobbyists each using a different method of water transfer and plant support. These can include the drip systems, ebb and flow systems, wick systems and aeroponic systems.
Hydroponic Nutrient Kits
While you can make your own homemade nutrients using fertilizer salts, to obtain higher yields and faster plant growth a number of hydroponic manufacturers provide nutrients that contain more than just the major and minor trace elements. These hydroponic nutrient kits contain crop enhancers such as root boosters, amino acids, microbes, enzymes, vitamins, fulvates, humates and a non-ionic surfactant.
A good hydroponic nutrient kit contains all or most of the above enhancers, be easy to use and provide a more than one part formulation containing different formulas depending on whether your plant is in the growth or bloom stage of development.
Growing Hydroponic Fruits and Vegetables
Hydroponic growing systems are suitable for growing a wide variety of fruits and vegetables. If you live in a relatively small space, like an apartment, an indoor hydroponic herb garden can be a perfect way to ensure there’s always a fresh, organic supply for your meals. Below, we provide information and how-to guides for some of the most popular fruits and vegetables being grown in hydroponic home gardens.
Growing Hydroponic Tomatoes
Tomatoes are highly delicious and nutritious fruits that can be a significant contributor to a healthy diet. However, ensuring a constant supply of tomatoes all year round can be a challenge. Usually, tomatoes that are grown outdoors are affected by weather conditions. So how do you ensure a constant supply of fresh tomatoes regardless of the weather conditions? Growing tomatoes in hydroponics system is the answer.
Hydroponic Tomato Conditions
pH Level: Tomatoes prefer a nutrient solution pH between 6.0 and 6.5
Growing Medium: Rockwool works well because of its ability to hold water.
Temperature: The ideal temperature for tomatoes would be between 64 to 77 °F ( 18 – 25 ° C) during the day and 54 to 64 ° F (12 to 18 ° C at night)
Lighting: Full-spectrum LED for about 18 hours a day
Hydroponic Tomato Step-by-Step Guide
- Grow tomato seeds – This should be done inside the hydroponics system on nursery tray. Soak the special growing material on the nursery tray with pH 4.5 water. Then plant your seeds on the surface under a transparent plastic dome to encourage sprouting of seeds. Once the seeds have sprouted, the covering should be removed and place your seedlings under artificial light source for about 12 hours a day. Try to avoid using incandescent light bulbs because they can damage the seedlings.
- Move the seedlings into the hydroponics system – This should be done when the seedlings are about 10-14 days old and have got the first true leaves. On the hydroponics system, place the seedlings at a spacing of 15 cm apart. Alternatively, you can transfer the seedlings to the individual plastic pots containing the special growing material.
- Set the water pump timer – Set the pump to run for about 30 minutes once in every six hours. However, you may need to increase the watering frequency if the tomato plants begin to wilt. On the other hand, the watering frequency is decreased if the roots become soaked. Also, it is important to note that tomatoes require more water when they have begun blooming and fruiting.
- Set artificial lights – The growing tomatoes should be exposed to between 16 to 18 hours of artificial light a day. This should be followed by 8 hours of total darkness.
- Stake and prune tall tomato plants – Tomato plants that grow indefinitely require staking in order to grow in an upright position. Moreover, you can prune the plants by breaking off the stems with your hands.
- Pollinate the tomato plants – Remember that there no insects to pollinate the plants, so you have to do it yourself. Use a soft paintbrush to transfer pollen from the stamens to the pistil of tomato flowers. The process should be repeated daily. After this, you will wait for the tomato harvest.
Growing Hydroponic Lettuce
Apart from growing hydroponic tomatoes, lettuces have to be the second most popular vegetable to grow using a hydroponic system. They are low maintenance and unlike soil grown lettuces they are less likely to be eaten by pests such as slugs and caterpillars. Secondly, hydroponic lettuces are easy to prepare as they will not involve so much washing to remove soil and insects from the leaves.
You can use a variety of different hydroponic systems for growing hydroponic lettuce. Whatever system you use the lettuces spacing should be approximately 6 inches apart as lettuces require plenty of light and you don’t want the lettuce leaves overlapping.
You can grow hydroponic lettuces next to a sunny window or for better results get yourself a compact fluorescent grow light for under $75 with a bulb between 100 and 200 watts.
Good Hydroponic systems for growing lettuce include the ebb and flow method, the Nutrient Film Technique (NFT) or just a basic lettuce raft consisting of a shallow reservoir pan, an aquarium air pump, and a rigid Styrofoam sheet to hold the net cups in place that contain the lettuce seedlings.
Hydroponic Lettuce Conditions
pH Level: Lettuces prefer a nutrient solution pH between 5.5 and 5.8
Temperature: Lettuces prefer cooler temperatures than most vegetables. The ideal temperature would be between 64 to 70 °F ( 18 – 21 ° C) during the day and 55 to 61 ° F (13 to 16 ° C at night)
Lighting: Compact fluorescents for 14-18 hours a day
Hydroponic lettuce nutrients: For nutrients, we recommend Flora Series nutrient solutions put out by GH (General Hydroponics). They are affordable and easy-to-use and consist of 3 parts (Flora Grow; Flora Micro; and Flora Bloom).
Hydroponic Lettuce Systems
Nutrient Film Technique (NFT): With the NFT system, a thin film of nutrient solution flows through plastic channels, which contain the plant roots with no solid planting media. This can be quite a complex system and not recommended for beginners. The advantage is that less nutrient solution is required.
Ebb and Flow / Flood and Drain system: This is a more simple and reliable method with fairly low initial costs. Pots are filled with a hydroponic medium which anchor the roots and the hydroponic solution floods the system and is allowed to ebb away.
Lettuce Raft System: The lettuce raft works well because it simple and cheap to setup and can be reused. The system just involves a reservoir tank or shallow reservoir pan, an air pump, rigid foam sheet, net cups, air stones, a small bag of Light Expanded Clay Aggregate (LECA), seed starting/rooting plugs, a ¼” compression grommet and of course hydroponic nutrients.
The lettuce raft system is best for a small crop of lettuces where you don’t want to buy an expensive or complicated hydroponic system. The nutrient solution can last a whole growth cycle and the nutrient solution only needs to be topped up with water every time it runs low. It also makes a great choice for school classrooms.
Growing Hydroponic Strawberries
Nothing tastes better than strawberries. From candies to yogurts, you will find strawberry flavor. How can you ensure regular supply of fresh strawberries all year round? The answer is to grow strawberries in the hydroponics system. In this case, you will get a constant supply of fresh strawberries and even sell the surplus.
Hydroponic Strawberry Conditions
pH Level: Strawberries prefer a nutrient solution pH between 5.5 and 6.5
Growing Medium: LECA, expanded clay pellets or heydite, or crushed shale rock work very well for strawberries.
Temperature: Suitable temperatures for strawberries would be between 59 to 80° F ( 15 – 27° C) during the day and 54 to 64° F (12 to 18° C at night). According to researchers, the optimal temperature for strawberries is 68° F (20° C).
Lighting: HID and T5 light sources for 12-16 hours per day.
Hydroponic Strawberry Step-by-Step Guide
Strawberries grown from the seed takes up to 3 years to start bearing fruits. This is not advisable for hydroponic growers. Ideally, you should buy certified runners from reputable dealers. These runners are off-shoots that are cut from a mature strawberry plant.
- Buy the nutrient solution – For optimum growth, Strawberries require nitrogen, potassium, and phosphorus. The other main elements required by strawberries are magnesium, calcium, and sulfur. The trace elements needed by strawberries include manganese, copper, iron, molybdenum, cobalt, zinc and chlorine.
- Prepare the container for growing strawberries – You will need a 5-gallon food-grade plastic bucket to grow hydroponic strawberries. Avoid containers that contain chemicals including paints. Ensure that your container is clean and dry. Then fill up to two-thirds of your container with a pre-soaked growing medium. In this case, vermiculite is the ideal growing medium for strawberries
- Plant your strawberries – If you are transplanting the strawberries from the soil, remove the attached soil with mild shaking. Then soak the entire roots system in a different bucket of cool water. Wait for about 15 minutes, then remove your strawberries from the bucket and rinse them with the fresh running water. Remove any dry or discolored leaves before placing your strawberries on the pots. Holding the crown, put the roots above the growing medium. Then add the growing medium to cover the roots. The crown should be exposed to the air.
- Provide the light source – 12- 16 hours of light per day is the best. In this case, you will need to install grow lights in your grow room.
- Provide nutrients – Remember that your strawberry requires a constant supply of the nutrients. In this case, you should mix the nutrients as the directions of the package. Then water your strawberries with this nutrient solution. The nutrient-rich water should be added on a daily basis to ensure the optimum growth of your strawberries.
- Ongoing Care – Premature flowers should be removed until the plant is capable of supporting the weight of the berries. Moreover, runners that appear should be removed even if the plant has reached maturity. Such runners use energy at the expense of fruiting. You may save some runners to grow more plants. Once you have started picking strawberries, they will not continue to ripen. In this case, you should avoid harvesting them before they are fully ripe.
Additional Hydroponics Learning Resources
- Hydroponic Gardening: Past, Present and Future
- Best Affordable Indoor Hydroponic Systems
- Hydroponics | Alternative Farming Systems Information Center
- Hydroponics and Education
- Hydroponics as a Hobby (free online book)
- Hydroponics and Space Settlement