How To Grow Hydroponic Tomatoes

Thomas Angas by Thomas Angas | Last Updated: March 17, 2020

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Today you’re going to see exactly how to grow hydroponic tomatoes year-round, understand which varieties are best suited to hydroponics.

In fact, we’re even going to recommend the best system setup to optimise your system for the best yields!

Let’s get started.

Picture of tomatoes

How To Grow Hydroponic Tomatoes

Tomatoes are one of the best crops to grow in a hydroponics system. They’re hardy and respond extremely well to being grown in an indoor environment.

You might have read that tomatoes are difficult to grow, and while they’re certainly harder than say lettuce – they aren’t as tricky as you might have been lead to believe.

As long as you choose the best hydroponics nutrients, the right lighting and tend to your plants then you’re almost guaranteed to be enjoying the fruits of your labour in a couple of months.

Seeds Vs. Saplings

So before we get deep into the how, first we should take the time to understand which is the best way to start – either with tomato seeds or sapling plants.

While saplings are the easiest route to get started they do come with some issues. Plants grown outside can be contaminated by pests and bacteria which could potentially ruin a crop. That’s why most veteran growers will grow their seedlings indoors.

Getting Started

To grow seedlings indoors start by placing seeds in a tray filled with a growing medium, wet the medium with water (a pH of 4.5 works best) then keep the seeds covered in a moist, damp area with a temperature of 20-25 degrees Celsius / 67 to 77 degrees Fahrenheit.

As soon as you see the seeds sprout you should transfer them into your hydroponics system ensuring there’s adequate light.

The Right Lighting

If there’s one thing that tomatoes love it’s light.

In fact, they’ll need around 8-10 hours of light per day with some varieties needing upto 18 hours! Once the plants mature they’ll then need around 8 hours of darkness per day to allow for respiration.

When it comes to lighting, your best choice is to use metal halides, however, you’ll still be able to get good results using CFLs and LEDs.

Temperature Range

While tomatoes can tolerate temperatures from 13 degrees Centigrade / 55 degrees Fahrenheit the sweet spot is normally 20-25 degrees Celsius / 67 to 77 degrees Fahrenheit during the day and 13-18 degrees Centigrade / 55-64 degrees Fahrenheit at night.

Anything lower than this and you risk killing the plants which is why a grow tent can be a useful tool to maintain temperatures.

Hydroponic Nutrients for Tomatoes

In order to grow well, tomatoes require a lot of nutrients and if you’re looking for a bumper crop you’ll want to look for a plant nutrient mixed designed for tomatoes.

These specialist tomato hydroponic mixes are higher in phosphorus, nitrogen and potassium which are the nutrients the plants crave!

pH & EC Requirements

Tomatoes like a slightly acidic pH of between 5.8 to 6.3 and EC levels of between 2.0-3.5 milliMhos.

While a pH meter can be extremely useful, there are certain things to look out for that will provide a quick check on how your plants are doing:

Grow Media

With the right grow medium you can almost guarantee a high yield. Tomatoes, unlike many other crops, actually do well in a number of different grow mediums.

Here a few of our favourites below:

Systems For Tomatoes

While tomatoes are hardy enough to grow in a wide range of hydroponic systems, due to the high amounts of nutrients needed, some hydroponic systems aren’t as suitable.

A good example of this is that while a recirculating system will work in the early days of your plants live, once they start flowering pH management can be a nightmare.

You should consider:

Best Tomato Varieties for Hydroponics

With thousands of tomato varieties available, how do you pick the right one for your hydroponics setup?

Determinate Vs. Indeterminate

There are two types of tomato – determinate or indeterminate so which is right?

Indeterminate

Indeterminate tomato plants will grow up on a vine and with pruning and support will repeatedly grow bear fruit.

Determinate

Determinate plants, on the other hand, will spread out horizontally along the ground and only grow vertically up to four feet.

Determinate plants are the most popular amongst hydroponic gardeners.

Our Top Choices

Here are some of our favourite hydroponic tomato varieties:

The Bottom Line

Growing hydroponic tomatoes can be great fun. For those looking beginners looking to step up from leafy greens will enjoy the extra challenge of nutrient management and seeing your plants flower and fruit.

Thomas Angas, the founder of Authority Gardening lives with his wife and two darling pups. He spends his free time writing, hiking and learning how to become a better gardener. He launched Authority Gardening in 2017 to help people all over the world their gardens grow.