How to Grow Hydroponic Tomatoes? Steps & Pictures

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Have you ever heard of hydroponics? That fast and healthy way to grow vegetables – WITHOUT USING SOIL?

It happens to be one of the best ways to grow ANYTHING. And when it comes to hydroponic tomatoes, this holds even more truth.

If you grow hydroponic tomatoes well, you can expect them to be GIGANTIC, HEALTHY, and SUPER-TASTY.

They will also grow faster than they would in crops. And if that wasn’t enough, you won’t have to worry about pests or diseases.

Doesn’t that sound like a great idea? Let’s show you what you need to make that happen!

What Do Hydroponic Tomatoes Need to Grow?

What Do Hydroponic Tomatoes Need to Grow

Tomatoes are often easy to grow. But they won’t grow alone like succulents, for example.

To keep them healthy and thriving, consider these factors:

Growing Medium

You’ll forget about potting soil completely. Hydroponics uses a growing medium instead.

This growing medium does the same job as soil but without any of the drawbacks.

Of course, the growing medium will depend on what hydroponic system you’re using (and maybe a little more expensive than soil itself), but it is a lot healthier.

Here are some growing mediums to consider:

  • Coco coir (coconut husk)
  • Expanded clay (pellets or pebbles – typically called grow rocks)
  • Gravel
  • Hay
  • Perlite (volcanic rock)
  • Phenolic foam (peat foam)
  • Rockwool (volcanic rock, coke, and limestone)
  • Sand (sterilized)
  • Sawdust (or mulch)


Because you’re taking away the soil, you’re also taking away a significant part of the nutrients. You won’t be using compost or manure either, so that’s even fewer nutrients for the tomatoes to use.

What can you do in that case?

Here’s where nutrient mixes enter into action. While you can use typical fertilizer (powdered or pellets), the liquid mixes have no competitors.

Even then, you still need to use at least two different liquid fertilizers for the best results. This includes fertilizers with macronutrients like:

  • Nitrogen (primary nutrient)
  • Phosphorous (second most important)
  • Calcium (vital for yields)
  • Potassium (vital for yields)
  • Magnesium
  • Sulfur

These will be super-helpful when your tomatoes start growing. Having said that, they’re often not enough.

That’s why a second fertilizing mix, preferably made of micronutrients, is an excellent idea. Among micronutrients, you’ll find:

  • Boron
  • Zinc
  • Manganese
  • Iron
  • Copper

Just be aware that tomatoes will need more nutrients in some cases (when the fruits start to appear, for example) than in others. We’ll teach you how to apply them later.

ADVICE: You can always go for tomato fertilizers. These mixes are specifically made for this plant.

Water and pH Levels

Some people may struggle growing tomatoes, and the main reason is probably high-pH water.

Believe it or not, most residential water has 8 pH or more. This is way too alkaline for tomatoes, which prefer acidic water with pH levels between 5.5 and 7.

The reason pH levels are so high in tap water is corrosion. Acidity in water increases the amount of rust in pipes, so water-delivery companies often make the water more alkaline to prevent that.

As hydroponics need a lot of water to function (that’s where the hydro comes from), you’ll need to make sure the water is suitable. Before starting your hydroponics, check your tap water pH level. In case it is higher than 7 pH, you will need to lower it manually.

Related: How to Lower the Water pH On Your Pool

Sunlight or Artificial Light

You need to ensure a lot of light while growing tomatoes, whether they’re in garden crops or hydroponics.

They thrive with sunlight and struggle with too much shade.

For outdoor hydroponics, this will be a no-brainer. Just keep them in places where they receive no less than 6 hours of daylight. If you want the fruits to grow faster and bigger, keep them with no less than 12 hours of daylight.

But ensuring enough light when you’re growing tomatoes indoors can be more difficult. Here’s where grow lights and other artificial alternatives enter into action. In that case, the amount of light would be about the same (at least 10 hours).

Stable Temperatures

The last thing hydroponic tomatoes need is a stable environment. If you can’t provide temperatures between 55 degrees Fahrenheit at night and no less than 60-to-80 degrees in the day, your tomatoes will be doomed.

Here’s where many appliances like heaters and vents enter into action. They provide the warmth necessary for tomatoes to thrive.

If you’re growing them in a warm area outdoors, the extra appliance may not be necessary.

Grow tents and greenhouses always help to keep temperatures more stable, so don’t overlook those if you can afford them.

How to Grow Hydroponic Tomatoes: Step-by-Step Guide

You can now start growing hydroponic tomatoes. You’ll have to be prepared for the job as hydroponic systems aren’t as easy as they seem. But you also need to be relaxed, as it isn’t rocket science either.

Here are the steps to take:

Step 1: Choose a Hydroponic System

Before you start, you must pick a suitable method.

There are many hydroponic systems to go for, and they all have different ways of growing your tomatoes. Luckily, tomatoes grow well with either of them – so you don’t have to think too hard about it.

Having said that, you must consider your needs and available space. Some hydroponics consume more space and water than others. Likewise, some are a bit complicated to make but will allow you to grow more tomatoes, while others are easier to build but don’t offer as much space.

TIP: As you’re likely a beginner, it’s always worth trying with a novice-friendly method. For that, you can find hydroponic kits, specially made for tomatoes in some cases, that save you a lot of hassle.

RELATED: 19 DIY Aquaponics Plans to Build in your Backyard

Step 2: Look for the Perfect Place

Look for the Perfect Place

Look, you can absolutely grow your hydroponics outside. There shouldn’t be any problem as long as water flows freely.

But there’s no much of a point in that. As your tomatoes will be exposed to pests that could stump their growth.

That’s why the perfect place is always under a greenhouse or grow tent. If you can’t install one of those, an indoor environment (like a garage, a backyard shed, or even an enclosed patio) will be enough.

But there’s a catch: the environment must stay warm for the tomatoes. The humidity should not be too high, either. Otherwise, the tomatoes may struggle.

CONSIDER THIS: For outdoor hydroponics, adding polyethylene covers or transparent walls could be enough to prevent pests from damaging the tomatoes.

Step 3: Install the Grow Lights (If Needed)

To ensure the place is PERFECT, nothing will help you more than a set of grow lights.

Artificial fluorescent or HPS lights are super-helpful in case you’re growing them indoors. They keep your plants growing sustainably and processing nutrients more effectively.

WHAT TO KNOW: Greenhouses with transparent walls and roofs may not need to grow lights at all. But consider getting a pair if you’re using a grow tent.

Step 4: Set Up the Medium and Seed Trays

You can now plant the tomato seeds.

Of course, you’ll have to plant them in the growing medium of your preference. Most likely, you’re choosing Rockwool or expanded clay, as they work with pretty much any hydroponics system.

Regardless of your choice, it’s essential to soak the material first. Each block or portion of the material should be wet.

Then, place the material in the seed trays (if any). A DIY pot may get the job done too.

Finish by letting the seeds sprout. This should take between 5 and 15 days.

Step 5: Keep the Seedlings Lighted

Keep the Seedlings Lighted

As the seed sprout and the seedlings start to grow, you need to keep them under enough daylight. This could be either the grow lights or sunlight itself.

In this period, the light is CRITICAL. You need to keep the growing tomatoes under the light for AT LEAST 12 hours straight.

REMEMBER: Sunlight and grow lights can be a little damaging, especially in the summer. To avoid harm, keep the roots covered if possible.

Step 6: Install the Plants in the Hydroponics

Sooner than later, those seedlings will become adult plants. Before that happens, you need to place them in the hydroponic system.

When do you know it’s time to move them? As soon as you see roots growing away from the medium, that’s the moment. This happens when the seedlings have been growing for about 10 to 18 days.

As you’re transferring the seedlings to a new place, consider adding more growing medium (if the roots are overgrowing too fast).

Step 7: Prune to Promote Growth

Prune to Promote Growth

Within the next 40 days, the plant will become an adult. Several branches will grow off the main stem. Some of them will go to the sides.

Prune them.

As you’re growing hydroponic tomatoes, you need to cut off the branches going to the sides too far. This doesn’t only help to keep the plant growing straight, but it also promotes growth.

ALSO CONSIDER: Adding a stake as support helps the tomato grow straighter as well. This improves yields later on.

Step 8: Pollinate the Blossoms

Pollinate the Blossoms

Soon enough, the plant will start to bloom.

The blossoms pollinate themselves in the wild with the help of insects. This is less likely to happen in a hydroponics system – so you’ll have to do it by hand.

Luckily, it is nothing to be cared of. Here are some steps to follow:

  • Look for a cotton swab or soft paintbrush. A powder brush for makeup gets the job done.
  • Wait for the first blossoms to appear. Let the petals bend back first (1-2 days).
  • Then you can use the brush as a pollinating driver. Touch the pollen-filled stamens (cone-like part of the flower) and bring the pollen to the pistil (the green tube-like portion in the center of the flower).

Do this for all flowers if possible. Each flower you pollinate is more likely to become a tomato later on.

Step 9: Change Nutrients as Tomatoes Grow

Once you’ve pollinated the flowers, it’s worth changing the water and the nutrients.

An excellent thing to do is to replace the water in the reservoir with a new one. Then add the nutrients, focusing on nitrogen, potassium, and calcium.

This should help with the yields, producing more and larger tomatoes

Step 10: Let the Tomatoes Grow (and Harvest)

Let the Tomatoes Grow (and Harvest)

Your tomatoes will start yielding soon enough. This can take up to 80 days in some cases, so be patient if need be.

If you pollinated the tomatoes well, this shouldn’t take much.

Once the fruits come out, you can wait for them to grow big and then harvest.

You’ll have tasty and juicy tomatoes in your own hydroponic garden.

How to Care for Hydroponic Tomatoes?

How to Care for Hydroponic Tomatoes

You have a decent idea of what it takes to grow tomatoes. But how do you care for the plant as it grows?

Here are some pieces of advice that may help you:

Keep Temperatures Stable

We already said this, but it’s worth remembering.

Tomatoes don’t like temperatures under 55 degrees in the day. And as a maximum, they should receive 80 degrees.

Anything that goes too far up or down will cause the tomatoes some problems.

TIP: If temperatures are too high in the summer, you can always use a fan to ventilate the place. This should also reduce temperatures significantly.

Use Fertilizers Correctly

The nutrient mixes you’re using need to be liquid for easier absorption. Pellets and powders get the job done, but they mess up the water (dirty).

For that, it’s always better to mix the fertilizer with the water beforehand, making sure the nutrients are well-diluted. Then, you can start the pump or whatever system you’re using as hydroponics.

ADVICE: Avoid organic fertilizers, as these decompose less effectively and make even more of a mess in your system.

Test the water’s pH Consistently

Even if you’re using a filter to keep the water’s pH at the right level, it may still lower or increase too much.

The way to prevent that is to be testing it at least every week. Using a pH meter or test kit can be truly helpful in this case.

Be sure the pH level stays within 5.5 and 7 pH. Anything lower or higher than that will need some intervention.

RELATED: Best Soil Test Kit in 2022

Frequently Asked Questions (FAQs)

Q1. Should I use pesticides on hydroponic tomatoes?

If you’re growing them indoors, you’ll need no pesticides. For outdoor hydroponics, bringing natural pesticides like lacewings and ladybugs, plus tomato companions, may suffice.

Q2. How fast do hydroponic tomatoes grow?

It depends on what kind of tomatoes you planted. Some varieties grow in as little as 50 days, while others may take over 70 days. The difference is their size. The fastest-growing varieties bloom and produce tomatoes a lot quicker.

Q3. Do hydroponic tomatoes taste good?

Yes. They’re actually better-tasting than wild tomatoes for the simple reason they’re not exposed to unhealthy soils, pests, or diseases.

Q4. How to support hydroponic tomatoes?

Also known as staking, this process is about placing a small stake, pole, or board close to the stem. Tie the plant to the piece, and that should keep it upright. For an even straighter plant, you can attach a string to the top of the plant that pulls up. This may also help with growth.

Grow Your Own Hydroponic Tomatoes TODAY!

Your hydroponic tomatoes will be tastier, bigger, and a lot healthier – FOR SURE.

As long as you follow our steps above and put every one of our advice into consideration, then you should have no problem growing those tomatoes.

For beginners, this may take a bit more effort and time than usual. But for an expert or seasoned gardener, this may be as easy as 1-2-3.

Either way, WHAT ARE YOU WAITING FOR? Those hydroponic tomatoes won’t grow themselves!

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