How to Grow Marijuana in a Hydroponic Tray

How to Grow Marijuana in a Hydroponic Tray

If you're tired of buying marijuana that isn't as fresh as it could be, or if you want more control over the quality of your weed, it's time to start growing your own plants. Hydroponic systems make this process easier than ever before, but they do require some specialized equipment and attention. Here are some tips for setting up a hydroponic tray and getting started with your new marijuana garden!

Germinate marijuana seeds.

To ensure that you get the best possible seedlings, germinate your marijuana seeds in a hydroponic tray. This will allow you to control the growing conditions and prevent diseases from spreading too quickly in your cannabis plants.

To germinate cannabis seeds:

  • Use clean water and a small bowl or jar for soaking the marijuana seeds for 24 hours before planting them in soil or rockwool cubes.
  • If using Rockwool Cubes, prepare a medium-sized container with holes drilled into it so that water can drain out easily when watering is required. Fill halfway with hot water then add cold water until they are completely submerged (you can add nutrients if desired). Allow them to soak overnight at room temperature (70 degrees Fahrenheit) then rinse well under running tap water before planting them into net pots which have been filled with dampened potting mix (or perlite).
  • Place each seed on top of its own individual square of toilet paper - this will act as an “egg carton” which prevents roots from forming prematurely when placed directly into soil below.#ENDWRITE

Soak the cubes in water for 24 hours.

Soak the cubes in water for 24 hours.

  • Before you can plant your marijuana seedlings, you'll need to soak them in water. To do this, place your seeds into a glass of warm tap water and leave them there for 24 hours. This will help the roots grow stronger so they have a better chance at surviving in their new home.

Place a marijuana seed on top of one of the cubes.

Gently place one seed in the center of the cube. You can use a toothpick to help position it, but don’t cover the seed with soil or anything else. It is best to only plant one seed per cube, as most trays will be too small for more than one plant.

Cover the tray and keep it in a dark place.

Once the seed has germinated, you need to keep it in a dark place for 24 hours. The dark period is important for the marijuana plant to continue with its development process. If you are using a plastic bag or wrap, cover your tray and let it sit in a dark place for 24 hours. You can also use a cloth or towel to cover the tray as well.

Keep the tray near a light source that's bright enough to read a newspaper by.

You need to keep the tray near a light source that's bright enough to read a newspaper by. The best way to do this is with an LED grow light, which can be purchased at most hardware stores and online retailers. Make sure you place it within 3 inches from your plants and leave it on for 18 hours per day.

Change the water every day.

The most important part of growing marijuana in a hydroponic tray is changing the water every day. You should change the water in your tray every day, and you should make sure that you're using clean water that has been dechlorinated and filtered.

Some people are concerned with adding nutrients to their plants' drinking water, but there are plenty of commercial products available for this purpose if you want them—and it's generally better than just adding nutrients to the soil in which your plants grow, as well as more sanitary (since potting soil can carry bacteria).

Allow the seedlings space to grow as they sprout.

When you first put your seeds in the tray, it's important to remember that they need space in order to grow. If you crowd them together too much, they won't be able to grow properly. On the other hand, if you give them too much room, they'll have too much room for their roots and not enough light for their leaves (which is what produces energy).

So how do you know how much space your seeds should have? It depends on how big you want your plant to be at harvest time! If this wasn't a hydroponic system without any soil involved—and if we were talking about cannabis plants growing outside instead of inside—then there would be some standard idea of how large each part of a cannabis plant should get before harvest time came around (meaning: when buds are ready). But since we're dealing with hydroponics here and everything happens faster than usual (since there is no soil), it's hard to say exactly how many inches tall or wide any given strain should get over its lifetime.

Swish the plants around in the water gently with your hand daily to oxygenate them until they have their first set of leaves.

  • Swish the plants around in the water gently with your hand daily to oxygenate them until they have their first set of leaves. The roots need oxygen, so it is important that you keep your plant well-oxygenated while they are young, as this will help them grow strong and healthy.
  • Hold the leaf by its stem between two fingers, then dip in water for 10 seconds or so (keeping track of time), before placing back down into the container. It may take several dips for all of the leaves to be wetted, depending on how many there are and where they're placed in relation to each other within the tray itself.
  • Continue doing this until you see new growth appear on top (around three weeks after germination).

Once the roots are 4 inches long, prepare them for transplanting.

Once the roots are 4 inches long, prepare them for transplanting. You should look for healthy roots that are not damaged in any way. The reason we’re checking for damage is because if there is an injury to the root, it could cause problems later on.

As mentioned above, only transplant healthy plants into your final hydroponic tray. If you don't check your plant's roots now and find out they're too short or tangled up in the grow medium, then you'll need to cut off those sections of damaged roots before transplanting into your final tray (or even worse: throwing away a perfectly good seedling).


Growing marijuana hydroponically can be fun and rewarding, but it’s also a lot of work. The key to success is following the steps outlined above and keeping them in mind as you grow your plants. As long as you do that, they should stay healthy and strong throughout their life cycle!