SIMPLE DIY Guide on How to Start Seeds for Hydroponics! | 🌳

Most hydroponics gardeners have probably been there; your garden is all set up, and all that remains is to plant your first seeds. There are numerous upsides to planting your own seeds as opposed to purchasing seedlings from retailers. By starting your seedlings, you have better control over the nutrients, light, water, and air that gets to the seeds. However, doing this might not be as easy as it sounds. Starting your own seeds requires some skill and attention to detail. So, how can you start seeds for hydroponics? Luckily, we have come up with some useful, easy-to-follow steps towards ensuring success in this gardening endeavor.

Get Your Materials

As you might probably imagine, starting seeds for hydroponics will require some materials. Here is a look at some essential ones, some of which are optional depending on the scale and gardening method.

Planting Medium

Your seeds need to be placed in a growing medium that facilitates root development and growth. While one might easily overlook the essence of choosing growth media, it is one of the most important determinants of seedling health. Some of the most popular options in this regard include coco coir or Rockwool. These growth media come in small cubes known as starter plugs that easily hold water and air. Most of these plugs have holes into which the seeds are planted (the exact number depends on numerous factors).

One advantage of using starter plugs instead of garden soil is that the gardener does not have to transplant the seeds once they are ready. You can just place the entire plug onto another growth medium. Besides using starter plugs, you can also choose to use another growth medium known as a rapid rooter. This one is made from fully organic matter such as peat and tree bark. Rapid rooters often contain useful microbes that enhance nutrient absorption and seedling growth.

If for some reason, you do not prefer growth media, you can go the soilless way and use vermiculite or perlite as your growing medium. Like the plugs, you would have to fill a container with your material of choice and plant the seeds.


If you decide to use rapid rooters, Rockwool cubes, or coco coir cubes, you will need net-cups to hold the cubes and prevent them from disintegrating. Some well-designed cups come in trays with multiple spaces for placing cubes. Keep in mind that net-cups come in different sizes. The larger the cup is, the more planting media it will require to fill.

Seedling Tray

You will probably be planting tens, maybe hundreds of seeds in a single season. If this is the case, you will definitely require a seedling tray that can easily hold multiple net-cups. Ideally, the tray’s depth should range between four and six inches. If possible, go for trays with advanced features such as cloner systems. With such a system, your seeds have easy access to the much-needed nutrients, air, and water. If you are a beginner gardener, though, a simple seedling tray will do just fine.

Heating Mat

Most seeds germinate well in specific temperature ranges. If you live in an area where average temperatures are way below the seeds’ requirements, you will need to invest in a heating mat. This relatively simple device is usually placed under the seedling tray and provides warmth to the ungerminated seeds, greatly enhancing the germination rate. Keep in mind that most seeds will lay dormant if the ideal temperature requirements are not met.

Grow Lights

A grow light is one of the optional components for seed starting. If you live in an area that receives adequate sunshine, then there is barely any need for having a grow light. It is also worth noting that seeds have varying light requirements for germination. If your seeds require light to germinate and your indoor garden conditions do not have such light, you will be better off purchasing a grow light to illuminate the entire seedling tray.

Nutrient Solution

Seed-starting nutrients come in different types. The most common varieties include the regular nutrients, half-strength, and diluted. Additionally, you may also find specialized nutrients developed specifically for a particular seed variety. Keep in mind that almost all seeds have sufficient nutrients to germinate without additional assistance, though.

A Ziploc Bag

A Ziploc bag apparently helps seeds germinate better. If you would like, feel free to give it a try and observe whether it provides any discernible advantages.

Fill the Cloner with Water

A seed cloner [1] is a gardening container designed to hold several net-cups at a go. On the other hand, the latter contains the growth media such as coco coir, Rockwool, or rapid starter cubes. If you decide to use a cloner, it is important to have the water level get to about half your cubes’ height. When doing this, ensure that the cubes are thoroughly moist. Please note that Rockwool has a considerably high pH and needs to be washed in diluted vinegar to make it suitable for seeds.

While using plain water will still work, it is better to fill the cloner with a mixture of water, blooming mix, and hydroponic nutrients. Keep in mind that you will need to maintain the water level regularly; if it drops below the cubes’ halfway line, top-up immediately. If the water level exceeds the cubes’ halfway line, your seeds might die due to excessive water. Feel free to use regular tap water or distilled water during the early stages if that’s up your alley. The only factor to keep in check is the pH level, for which you should aim for anything between 5.5 and 6.0.

Place Starter Plugs and Seeds

Now that you have your materials and seeds ready, it is time for arguably the most important planting step, placing the seeds into the starter plugs.

How to Plant the Seeds

The exact planting process to follow varies slightly depending on the planting medium. For example, one supplier might ship their Rockwool cubes with predrilled holes while another might not. If you purchase the latter, you will need to drill a hole not deeper than a quarter-inch. Once the hole is ready, all you need to do is place one or two seeds into the hole. Remember that you may need to gently push the seed into the hole, especially if you are dealing with super light seeds. Make sure to add some growth medium atop the seed to cover it.

Once you are done planting the seeds, make sure to cover the entire seedling tray. However, if you are dealing with seeds that require some light to germinate, feel free to skip this step. Most seeds will germinate excellently in total darkness, though. It is also worth noting that there is no guarantee for 100% germination. If possible, place two seeds in each cube to improve the chances of sprouting.

At this point, you can optionally cover the seedling tray with a zip-lock bag to lock in moisture and keep away light. The ideal germination temperature varies slightly among different seed types but generally lies around 68℉. If your nursery or germination area is significantly colder than this, make sure to place a heating pad beneath the container with the seeds.

Waiting for Germination

Once you are done planting the seeds, there is not much left to do besides waiting for germination. However, you will need to regularly need to check the water level if using a cloner. If you are using Rockwool as a germination medium, you might not even need to check the water level since the media can easily maintain the correct water-air balance.

Depending on the specific seed types, germination will take place in three to seven days. Some seeds might take longer than this, although, under ideal conditions, that is quite rare. Once the seeds have sprouted, make sure to chop off the extra seed from each cube if you have planted multiple ones. Only leave a single seedling in each cube.

While seeds will germinate excellently in darkness, they cannot thrive in the absence of light. This implies that you have to uncover the sprouts and place them in an area with some sunshine exposure or illuminate them with a grow light. When using the latter, make sure the seedlings have begun to develop their second set of leaves before placing them under artificial light. When using natural light, make sure to expose the seedlings to the morning sun since it contains many red light waves. As the seedlings grow taller, you will need to increase the amount of light they get each day.


Maintaining a seed-starting system is not overly complicated but requires quite some effort. Here is a look at some of the steps [2] you can take to ensure your hydroponics seeds start in the best way possible.

Sprinkling Cornmeal or Moss

While not advisable, some gardeners use garden soil to start their hydroponics seeds. Doing this exposed the little seedlings to damping off, wilting, and other fungi-related issues. However, one can prevent this by sprinkling cornmeal or sphagnum moss on the soil’s surface. These materials remove excess moisture from the soil and act as natural fungicides, minimizing the occurrence of multiple fungi-related problems.

Light is Extremely Important

One might easily overlook the essence of light, especially for such young plants. However, some light waves are essential for growth and leaf development. When extremely young, ensure the seedlings get a few hours of light each day. This could be artificial or natural light. As the seedlings grow taller, increase the light exposure gradually. When doing this, ensure the tender plant leaves do not get exposed to scorching heat that might emanate from artificial light or sunshine.

Do Not Forget the Water Levels

Seeds require sufficient water to germinate and grow. However, excessive water can cause seed or root rot, resulting in eventual plant death. Unless you are using Rockwool cubes, it is crucial to keep water levels in check. When using a cloner, make sure the water does not exceed the growing cubes’ halfway line.

Feed Nutrients at the Right Time

In the early stages of germination, seeds and seedlings can survive on their internal nutrients. Generally, any seedling will have enough nutrients to germinate and form the first leaves. After this, you will have to keep the seedlings nourished. You can do this using a wide range of seed-starting nutrients available in gardening stores. As the seedling develops more leaves, it requires higher nitrogen intake for healthy leaf development and potassium for sustained root system development.

Why Planting Seeds is Better Than Seedlings from Stores

β€œWhy should I go through the entire seed starting process instead of purchasing seedlings?” This is a common question among several beginners, enthusiasts, and even seasoned gardeners. While purchasing seedlings is definitely easy, it comes with numerous drawbacks. Here are some of the major upsides to starting your own hydroponics seeds.

The Freedom to Choose

When you buy ready-to-plant seedlings, your choices are limited to what the store has in stock. However, by starting your own seedlings, you get a wider choice of seeds you can grow. As you can imagine, looking for and purchasing seeds is way easier than doing the same for seedlings.


A wide range of heirloom plants is usually only available as seeds. If you intend to grow such plants in your hydroponics garden, your only option becomes to start the seeds yourself.

Less Seed Trauma

A hydroponics system works without soil. When starting your own seeds, you can plant them in soilless media before moving them to the hydroponics garden. With purchased seedlings, on the other hand, you have no control over the initial grow media. If the seeds were planted in soil, they would have to be cleaned and rinsed before you can place them in the hydroponics system. This medium transfer rarely goes well with seedlings and often results in seed trauma.


Price is arguably the biggest upside to purchasing seeds instead of seedlings. When you buy seedlings from the store, the price includes the seller’s seed, germination, and maintenance costs. By starting the seeds yourself, most of the costs are transferred to you, resulting in a significantly lower price than buying seedlings.

Gardening Satisfaction

Most enthusiast gardeners will tell you there is some satisfaction in watching a plant through its entire lifecycle. By purchasing a pre-started seedling, you might be essentially robbing yourself of the opportunity to experience the little joys of gardening. Simply put, you might end up feeling like you cheated.

Why the Poor Germination?

As most gardeners can attest, seeds barely germinate in their entirety. There will almost always be a few that do not sprout. While this is quite normal, having an extremely low germination rate is not normal and often points to a problem. Here is a look at some of the facts that might contribute to poor germination.

  • Dried outgrow media: Seeds require a moist and warm environment to germinate well. When the growth medium onto which a seed is planted dries out, it can result in the seed’s death. This makes it important to maintain the ideal moisture levels.
  • Overwatering: In what seems like a reversal of the first point, seeds will also die when placed in an overwatered environment. If the growth media becomes too wet, seeds will rot and die before they germinate. Additionally, extreme wetness facilitates mold and fungi development, a factor that further prevents seed germination. To avoid overwatering, make sure to sprinkle instead of pouring water on the seedling tray.
  • Overfeeding nutrients: Ideally, you should only begin to feed your seedlings once they have sprouted and developed the first two leaves. If you mix too many nutrients into the growth medium before germination, it may change the conditions in disfavor of the ungerminated seed.
  • Temperature: Seeds require a warm environment to germinate. While the specific temperature varies slightly from one seed to another, very few seeds sprout in cold conditions. Additionally, extreme heat might also be detrimental to some seeds, leading to their eventual death. It is essential to keep the growth medium warm enough for germination but not too warm to mess up the seed.

Tips to Enhance Germination

Now that we have established the causes of poor seed germination let us go over some steps you can take to improve the germination rate.

  • Get rid of seed inhibitors: naturally, seeds lay dormant during extreme cold to prevent them from sprouting too soon. This dormancy is enabled by inhibitors found in the seeds. The most common inhibitor is Abscisic acid. As conditions become warmer, the inhibitor level decreases, making it easier for the seed to germinate. To overcome this issue in temperature-native plants, you can put the seed in a growing medium and place it in the fridge for a few weeks. Once removed, the inhibitor levels will automatically decrease, resulting in enhanced germination. Some seeds also have phenolic compounds that act as germination inhibitors until the seed gets sufficient moisture. To overcome this, soak the seed in water since the phenolic compounds are water-soluble.
  • Maintain the ideal temperature: We have probably mentioned temperature severally in this guide because it’s one of the most important germination factors. To enhance the overall germination rate, it is important to maintain the growing media’s temperature at the ideal level. The exact figure varies from one seed type to another. Keep in mind that if temperatures in the seedling tray exceed 90℉, there will barely be any sprouting.
  • Presoak your seeds: Presoaking seeds saturates their seed coats, making them easier to break open. However, if you intend to plant your seeds in a soilless medium, presoaking might not be important. On the other hand, this step might make all the difference to gardeners who plant their seeds in the soil.
  • Scarification: This is essentially a process to weaken a seed’s exterior to enhance germination. Naturally, scarification is done by birds and other animals. When starting hydroponics seeds, however, you might need to do the scarification manually. Some of the items you can use to weaken a seed’s outer structure include knives, hammers, sandpaper, or a metal file. To use the latter, run the seed’s surface along a metal file. Remember that scarification only works well on significantly large seeds such as those found in some fruits.


Starting your own hydroponic seeds has numerous advantages over purchasing pre-started seeds. However, the process requires quite some materials and effort by the gardener. By following the tips and guides outlined in this guide, however, you can get your started seeds in no time. Happy gardening!


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