The Best Seeds For Hydroponic Gardening

Whether you choose to grow plants as a hobby or for a living, there are some added benefits to owning a hydroponic garden. So how is hydroponic gardening different to using a traditional outdoor area?

The biggest difference is the automation, most hydropic systems are set up on timers to run with little effort. Since you’re growing in a controlled environment you no longer need to worry about pest control, weather conditions, or weeding. Sounds good right?

What’s even better is that hydroponic gardens grow much quicker indoors. That’s because outdoor gardens have to rely on the sun as their source of light instead benefiting from a long 18-22 stretch of direct light indoors. This along with the lack of extreme weather and drought allows growers to successfully take plants from seedling to adults much quicker in a hydroponic system.

Hydroponic basil seeds

Which Seeds Do Well in Hydroponic Systems

There are a few vegetables and herbs that do exceptionally well in hydroponics these seeds include tomatoes, peppers, lettuce, broccoli and leafy herbs like dill, mint and oregano. This is because they all have root systems that benefit from the constant moisture.

Another added benefit is that hydroponic gardens save an enormous amount of space. Vertical growing systems in particular are ideal space savers.

In this article, I will be exploring what kind of seeds are best grown hydroponically, what to grow them in, and how to grow them.

Sound interesting? Let’s get started!

Growing Vegetables Hydroponically


Lettuce is a great starter plant for beginners as it grows fast and responds well to hydroponic systems, especially for smaller setups like the AeroGarden. On average, lettuce is usually ready to harvest in as little as 3 weeks. You’ll be chomping on salad in no time!


Tomatoes are a great choice of seed whether planting outdoors, in a greenhouse, or hydroponically. Hydroponic tomatoes are easy to maintain and there are many different space saving varieties to choose from. Tomatoes require heavy amounts of water making this vegetable the perfect candidate for hydroponics.


You can grow peppers, or anything on this list in fact, at any time of year using a hydroponic garden. No more waiting until April/May/June to begin planting your seeds, these indoor environments allow growth whatever the time of year.

Peppers have the ability to grow much larger and are on average, much tastier than those grown in soil.


Broccoli is fast-growing but requires more maintenance than other seeds. Therefore, it may not be the best vegetable to consider growing if you are a beginner. That being said, Hydroponic broccoli with the proper care will offer a bounty of fresh sprigs for months to come.


Carnations. Chrysanthemums and Orchids are just a few species that do well when grown hydroponically. Hydroponic flowers tend to thrive better in these indoor environments than outdoors due to the controlled system and lack of pests and weeds.

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Which Seeds Do Not Do Well in Hydroponics?

Unfortunately, not everything grown in a hydroponic setting will be successful. Seeds that do not grow well in hydroponics include corn, potatoes, zucchini, onions, carrots and most other root vegetables. The amount of water available to these plants from hydroponics will prevent the healthy growth needed for a full harvest.

Large Fruits or Vegetables

It is extremely difficult to grow fruits and vegetables such as melons, zucchini, watermelons and corn. Not only do they need room to grow, some bare a lot of weight and can therefore be difficult to manage if you have limited space.


Potatoes outdoors

Both potatoes and sweet potatoes do not adapt well to hydroponic systems as they require plenty of sandy soil to grow and mature. Another reason is that the roots need space to grow, something which there is minimal room for in a typical hydroponic garden.


The same can be said for carrots, and other root vegetables that need plenty of room and soil to thrive. Hydroponic carrots are not impossible to grow, but it will be an uphill battle to grow one similar in quality to what you can get from an outdoor garden. plan for small tender roots and harvest regularly for best results.


As a root vegetable, onions are also difficult to grow indoors. The root or bulb of the onion requires room to spread and search for light and moisture.

The Best Growing Medium For Hydroponic Seeds

So, how does a seed grow without soil? Let’s take a look at the best growing mediums for these special seeds.


Rockwool is an inorganic material that is mostly used for soundproofing and insulation. It is made out of molten minerals, or rocks such as ceramics and slag.

In hydroponics, rockwool cubes are popular as they are a great source of insulation, they’re cheap, and they take up minimal space. Rockwool is pH neutral and is good at retaining moisture and oxygen; both of which are essential for a plant to thrive.

Clay Pebbles

Unlike rockwool or grow sponges clay pebbles offer an eco-friendly option to our hydroponic unit. These brown little spheres are easy to handle, and easy to clean allowing for re-use time and again. Clay pebbles are porous allowing them to hold water and nutrients vital for plant growth.

Grow Sponge

A grow sponge (as seen in AeroGarden kits), is made from peat moss (a soil amendment derived from peat bogs). They are used in hydroponics since they are affordable, lightweight, and retain a good amount of water. This water retention is important to mention as while the sponge is porous, it does not lie heavy on the roots of the plant.

Grow Bowls

Grow bowls are ideal for growing smaller fruits and vegetables such as strawberries, herbs, peppers, tomatoes, etc. These devices are a complete grow system for plants providing space to plant seeds with lights to grow under.

They are small, compact and able to hold multiple seedlings at once which makes them perfect for even the smallest indoor spaces.

How to Grow The Best Plants Hydroponically

Now you’ve read about what to plant and where to plant them, you’ll need to know how to care for your hydroponic plants. I’ll take you through everything you need to know about growing the best plants hydroponically.

Hydroponic seeds


Spacing is incredibly important when it comes to gardening outdoors, and it is just as vital in hydroponics. If your plants are too close together, there is a high chance that growing foliage will not have access to the light it requires. Therefore, I would heavily recommend keeping tabs on your crops and trimming them down as and when needed to prevent crowding. Leafy herbs like dill needs constant pruning to prevent flowering and stimulate growth.

Once indoor plants begin to grow into adults, it is at this point when growers tend to think about transplanting outdoors (I will go into detail more about this further down the article).

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Avoid Cross Pollination (Unless Intentional)

Traditional gardening often requires pollination, which is provided by bees and the wind. The same cannot be said for hydroponic systems.

While human intervention is the only way to pollinate indoor plants, you will find that many seeds planted hydroponically are of the self-pollinating kind. Vegetables such as tomatoes, peppers and peas, are all self-pollinating.

For those that do require pollination such as strawberries or cucumbers, there is a chance that pollen grains from each variation may cross over onto one another, thus resulting in a new variety of strawberry/cucumber.

While some growers purposely cross pollinate, there is a chance that the final product may not meet the requirements.

Nutrients and Plant Food

Plants require a total of 17 nutrients in order to successfully thrive. Therefore, it is essential to provide your crops with a good amount of nutrition.

Unfortunately, plants grown in hydroponic systems are less forgiving than those grown outdoors. So keeping an eye on nutrient consumption is key.

Water PH and TDS

Both the water pH and TDS (Total Dissolved Solids) must be up to scratch to grow healthy crops. So what are they?

Water pH (power of hydrogen) refers to the level of acidity or alkalinity in water. When it comes to gardening, this level should be between 5.5 and 6.5. If this pH level is too acidic, the plant will absorb toxic levels of nutrients. If too alkaline, the plant will find it hard to absorb any nutrients at all. Water is the foundation of the nutrient solution, so it is important to consistently check the pH levels.

Similarly, the TDS levels show how much salt and nutrients are available. TDS levels of 600 to 1000 are regarded as good, with 800 being almost perfect. If these levels are too low or too high, it can cause irreversible damage to your plants.

Care (Trimming)

Once your seeds have sprouted, your plants will begin to grow rapidly – which can sometimes become chaotic and stressful. I would recommend taking time out of your day (this could be a few minutes or even an hour depending on how big your system is) to tend to your growing plants to make sure they are getting all the essentials.

This will include trimming, misting, and repositioning your crops to ensure they have ample space and moisture to thrive.

Algae on growing medium

Cleaning (to Avoid Algae)

It is essential to keep your hydroponic system clean and free from algae, bacteria and pathogens. All of which can damage or even kill plants very quickly.

In order to ensure your indoor growing environment is clean, you will need to sanitize and sterilize the area frequently, especially after a harvest. There are many accessories to help you do so and they key is to keep on top of it by putting a cleaning schedule in place.

Transplanting your Hydroponic Plants

You may be wondering why anyone would choose to transplant indoor plants to an outdoor environment. Well, this could be for a number of reasons. Hydroponic growers choose to transplant crops when they have matured slightly and are ready for a life outdoors. For example, you may need to free up space, or you may have decided early on to transplant them outside once they begin to flourish.

Whatever the reason, you may wonder how to do it. Our step-by-step guide below is a good starting point. Let’s take a look.

Step #1: Lower The Amount of Water For Hydroponic Plants

About a week or so before the ‘big move’ you will need to reduce the amount of water you give to your indoor crops. This manipulates the roots so that they grow slightly and prepares them to search for water once in soil.

Step #2: Transfer Into a New Pot

Before transplanting outdoors, you will firstly need to move the plant into a pot of its own to help toughen up the cells before it is moved outside.

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A pot that is around 6 inches in diameter will suffice as the roots need space to spread (if transplanting a seedling).

Step #3: Fill It Up With Soil

To give your plant the best chance in the great outdoors, you should introduce it to soil early on. Filling your plant pot with potting soil. The softer and ample the texture and aeration is, the more space your seedling will have to grow successfully. Before adding the soil, you should mix with water in a separate pot. Be careful not to completely drown the soil in water as this could lead to root rot which will destroy the plant.

Step #4: Transfer The Plant To The Pot

To do this, simply dig into the soil with a large spoon to make enough room for the plant and its roots. This should be done quickly to prevent any damage. Therefore, if you are transplanting multiple plants, have the pots lined up and ready for the move. You may even want to trim or remove some of the leaves before transferring to minimize the risk of damage.

Step #5: Mist Your Transplants

Although the soil in the pots will already be moist, you should continue to mist the soil daily for at least a week. Adding fertilizer to your misting spray is essential so that your plant continues to receive nutrients.

After one week, you can reduce misting to once a week. Once the plant becomes accustomed to the new environment, watering will not be required as frequently.

Step #6: Let Them Toughen Up

By this, I don’t mean place them outside immediately in high wind speeds. This is a gradual process, so I would recommend firstly moving them into a room where there is plenty of natural sunlight.

Keep a close watch on your plant/s over the next few days. If you see any negative changes, try taking them away from direct sunlight and ensure the soil is moist.

Let them sit outside for an hour or two during the warmest times of the day and gradually extend this period until they are eventually outside permanently.

Hydroponic tomatoes

Hydroponic Seeds: FAQ Section

Take a look at my FAQ section to see if I can answer your question.

Are Seeds Better Than Clippings?

This depends on the plant in question but generally there is no right or wrong answer. While it is true that cuttings mature quicker than seedlings, there is also a chance that the original plant may have been affected by disease or pests which can therefore affect the plant you are trying to grow.

What Are Heirloom Seeds?

Heirloom seeds are seeds that have been passed down through generations, just like an heirloom. Such seeds are known for their distinguishable flavoring, adaptability or hardiness. Heirloom seeds are used to ensure a grower produces the same crop or plant year after year with the same great qualities.

What Are Dwarf Variety Seeds?

These are used to grow miniature versions of plants and vegetables. For example, cherry tomatoes, baby artichokes and green beans grown from dwarf seeds. These are ideal for hydroponic gardens as they require less space to grow.

How Do You Germinate Seeds Hydroponically?

I recommended using grow mediums specially designed for seed germination. Rock wool cubes are good for this”. It is best to germinate seeds before planting in a hydroponics system as they require a lot of moisture to grow.

When Should You Start Feeding Seedlings?

What most people love about hydroponics is that they are very low maintenance, particularly for the first week or two of growing. You should think about feeding seedlings once the first true leaves have formed.

Final thoughts

I hope you have learned something new about what seeds to use when it comes to hydroponics. If you are a newbie, or a keen grower yet to plant indoors, growing hydroponic seeds is a brilliant and interesting way of taking seeds to fully-grown crops.


Brock is the head gardener and editor-in-chief at Bigger Garden. Every year you can expect to see something new in his raised beds, from purple broccoli to cotton candy peppers.

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