How To Grow 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 guides on how to grow hydroponic fruits and vegetables for home gardeners.

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 a hydroponic system is the answer.

watering tomatoes

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

1. Grow tomato seeds

Growing tomato seeds 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 an artificial light source for about 12 hours a day. Try to avoid using incandescent light bulbs because they can damage the seedlings.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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. You can repeat the process daily. After this, you will wait for the tomato harvest.

Growing Hydroponic Lettuce

hydroponics

Apart from growing hydroponic tomatoes, lettuces have to be the second most popular vegetable to grow using a hydroponic system. These vegetables are low-maintenance. Furthermore, unlike soil-grown lettuces, pests such as slugs and caterpillars are less likely to eat them. 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.

grow hydroponic strawberries
Photo by Jez Timms

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 one would cut from a mature strawberry plant.

1. 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.

2. 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

3. 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. You should expose the crown to the air.

4. 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.

5. 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. You should add the nutrient-rich water 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, you should remove runners that appear 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.


Hydroponic Guide Sections

To learn more about other aspects of hydroponic gardening, see the following sections of our guide.