A Guide to Growing Hydroponic Tomatoes

Ah, the tasty tomato! From refreshing salads to intense curries, tomatoes are a staple ingredient of the modern diet, forming the base for a wide multitude of meals and snacks. Keen gardeners who have already grown tomatoes traditionally in soil will know that these delicate looking little plants are actually a lot hardier than they seem on first inspection. If this is your first time venturing into the world of tomatoes, then you’re in for a treat! Shop bought tomatoes are no match for their juicy, flavourful home-grown counterpart.

Different plants require different growing conditions, and the tomato is no exception. Although theoretically, they can be grown in any hydroponic system, there are a few growing methods that they favour. However, don’t give up on your tomato dreams if your system isn’t one of the chosen ones- just be aware that your produce may not grow as big or as succulent.

Hydroponic newbies who are just testing the waters have the luxury of foresight and can buy the system that best suits their plant requirements, so it’s worth investing a bit of time and doing your homework here.

Which Hydroponic System Is Best for Growing Tomatoes?

When it comes to tomatoes, there are three systems that favour optimal growth- N.F.T, ebb and flow and drip systems.


N.F.T systems are an excellent cost effective option because any excess nutrient solution is recirculated continuously. The tomato plants sit in baskets in a gully that is set at an incline, with their roots hanging freely into the root zone. The nutrient solution is pumped from the reservoir into the gully, where it slides down the incline, soaking the roots as it goes. Any excess solution then drains back into the reservoir, where it is recirculated.

If opting for an N.F.T system, investing in a backup generator is a good idea as the system is heavily dependent on a reliable electricity supply. Because the plant roots hang freely, there is no moisture retaining growing medium, so any interruption in the nutrient pump cycle could cause whole crops to dehydrate and die in a matter of hours.

Ebb and Flow

The ebb and flow (also known as flood and drain) method is similar to N.F.T, except the water pump is on a timer instead of being switched on continuously. The tomato plants sit in the grow tray with their roots supported by a growing medium. The pump comes on regularly during the day, pumping the nutrient solution from the reservoir into the grow tray.

While the pump is on, it floods the root zone with nutrient solution for a number of minutes. When it deactivates, gravity drains any excess solution slowly back through the delivery tubing. This solution is then recycled during the next pumping session.

Drip System

Drip systems offer the grower lots of control. There are 2 types of drip system- recovery and non-recovery. A recovery system will recirculate the excess nutrient solution, meaning it is extremely efficient. Non-recovery systems do not reuse the excess solution, and therefore require a precise digital timer to ensure that the plants remain hydrated and nourished.

In a drip system, tomato plants are supported by a growing medium. Nutrient solution is pumped from the reservoir up into drip lines, where it is then dribbled onto the growing medium. This allows for very even distribution of the nutrients.

Ultimately, each gardener will have different preferences, so it’s a good idea to weigh up all the pros and cons of a system before committing to a purchase. Time, money and what else you plan to grow are all important factors to take into consideration.

It’s also worth noting that whereas in the past, hydroponic systems were generally bulky equipment reminiscent of industrial machinery, nowadays you can buy stylish, elegant all-in-one kits that fit into any environment. Perfect for balconies and windowsills without compromising the décor of your home!

Ideal Growing Conditions Make Happy Tomato Plants!

Hydroponic gardening allows you to create the most ideal conditions to ensure that your plants reach their full growing potential. The grower has complete control over the environment. Nutrition, light and temperature are the three imperative elements of gardening, and with hydroponics, you get to play god and tweak them all however you wish!


Most varieties of tomatoes require lots of potassium and phosphorous, as well as a good calcium supplement to thrive. 3-part fertilizers are the best option to guarantee that your plants get all the nourishment they need to give you the biggest, juiciest tomatoes.

The PH should be maintained between 5.5 and 6.5 for optimal growth. Ideally, PH should be checked twice daily. Levels can be monitored using a simple affordable PH tester kit. Adjusting an inaccurate PH reading sounds complicated but it is actually quite easy to do using a PH adjustor which is added to the solution.

Electrical conductivity (or EC) is a simple way of measuring the strength of your nutrient solution. The higher the concentration of nutrients in your solution, the higher the EC reading will be. Tomato plants favour an EC reading of between 2.0 and 5.0. An EC meter will do all the hard graft for you here, ensuring that your tomato plants are getting the right strength of nutrients they need to blossom.


Light is another crucial factor in the hydroponic process. Tomato plants need at least 8 hours of light per day, so a decent light source will infinitely boost your growing potential. For basic setups, situating the system in an area of good natural light will help. However, if you are serious about growing the greatest crop of beefsteaks, then an LED light is a worthwhile investment to make. This gives you maximum control over the lighting.

Lighting is a hot topic in hydroponics circles, but something that is often overlooked is darkness. Plants need their beauty sleep just like people, so give them an adequate amount of downtime in darkness and they will reward you with a sweet bountiful harvest. Tomatoes photosynthesise best with an extended period of total darkness (up to 8hrs). Grow tents allow the cultivator to do this, while also protecting the plants from any other external pests or diseases.


Here is where hydroponic growing methods are really beneficial. Because you can control the climate, you can grow your tomatoes (or any other plant for that matter!) all year round. No need to go to Asia for your dragon fruit when you can grow them in the comfort of your own home!

Tomatoes are warm weather lovers, so keep your plants at a temperature of 18-25 degrees during the day and 12-18 degrees at night.

To grow your tomatoes in cooler weather conditions, you might need to use a heater to maintain the optimal growing temperature. Conversely, if you are in a hot climate, air conditioning will help to keep your plants at 25 degrees and under.

From Plantlet to Plump Fruit

So now you’ve got the lowdown on the necessary equipment and procedures, and it’s time to put the theory into practise. Here come your big, juicy, ripe tomatoes! Is your mouth watering yet?

Start Your Seedlings

It’s time to get those seeds growing! 1” by 1” inch cubes of rockwool make an ideal compact starter home for tomato seeds. Rockwell is an absorbent medium, meaning it holds moisture so seedlings stay hydrated without too much effort. Keep them moist and warm and your seedlings will germinate in 10-14 days.

Nursing Your Seedlings to Fruition

Nursing hydroponic seedlings to fruition does take a little bit of dedication and regular maintenance, but the amazing results make the effort so worthwhile. Finding the correct nutrient balance and keeping the reservoir topped up is your insurance policy to guarantee a fantastic harvest. Check your electricity dependent equipment regularly to ensure that everything is running smoothly, and monitor the PH and EC of your solution to confirm that plants are getting all the nourishment they need.


The tightly controlled growing environment of hydroponic systems means there is a lack of natural wind to aid pollination. As a result, pollination needs to be done manually by hand. Using a small fan regularly will help to circulate the pollen, but for a total no frills approach, tapping the flowers gently will dislodge the pollen from the male plants into the atmosphere.


It’s time to eat! Hydroponic tomatoes are usually ready for harvest in around 60 days. Signs of ripeness include a nice, uniform red colour and a consistency between firm and soft. Once you’ve given your fruit a good squeeze and are happy that it’s good to go, twist the stalk and pull the tomato away from the plant. And enjoy every delicious mouthful!

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