We have a cannabis seedling germination page which has everything you need to know about all the different germination methods, but this tutorial is different. In this hydroponic seedling tutorial I’m going to share exactly how I do my seeds from beginning to end in a DWC/bubbleponics setup!
Just follow these instructions and you’ll end up with healthy, fast-growing plants that germinate in just a few days. It’s pretty much fail proof!
Learn How to Start Seedlings So You Can Grow Hydroponic Cannabis Plants Like This!
Supplies Needed
There are a few different ways to get cannabis seeds, with the most common being ordering seeds online and growing seeds you find in weed that you buy. Learn how to research and find the right strain.
If you’ve found seeds, learn how to tell if they’re good to grow.
Here’s a picture showing several healthy and viable cannabis seeds
2.) Germination for Hydroponics
I’ve tried a bunch of different germination methods over the years, and the technique I prefer is for hydroponics is starting with the “Paper towel method” to germinate, putting the germinated seeds into Rapid Rooters, and installing the Rapid Rooters directly into reservoir. Lots of other germination methods as well, but this has worked best for me!
Paper Towel Method
This method is hard to mess up if you follow the instructions!
These seedlings were sprouted using the paper towel method!
3.) Place Germinated Seed in a Rapid Rooter
The Rapid Rooter should be cut open lengthwise
Gently place the germinated seed inside, root down
Most seedling plugs will go back into place easily, and you’ll barely be able to tell it’s been opened 🙂
4.) Prepare Hydro System for Its New Guest
If you haven’t put your hydroponic system together yet, now is the time! Make sure your pumps are all running, and that you’ve made a reservoir with seedling-strength nutrients. You need a home to put your new plants!
Learn how to set up a Hydroponic System
Hydro Tips & Hints
5.) Install Rapid Rooter and water the seedlings until roots reach the water reservoir – Turn on light to keep seedlings warm for best results!
Make sure to always keep the Rapid Rooter moist but not soaking wet.
If you have a top-feed, place the tube near the bottom of the net pot so the water isn’t soaking the seedling’s roots. You just want water dripping out the bottom so the root can use it for oxygen and water until it’s fully established in the reservoir.
Add your Rapid Rooter(s), and fill around the edges with extra clay pellets to hold each one in place.
Since your seed has already sprouted and been in placed into the right growing position, it’ll often pop its head out within just 12-24 hours! Sometimes you see just the leaves, but occasionally you actually see the seedling push the shell above ground. I keep the grow light on even before the seedling appears. It helps keep it warm and guide it toward the light.
When this happens the shell usually falls off on its own as the seedling grows!
The Rapid Rooter in this picture is a little too wet, which makes the seedling prone to “damping off.” If you ever notice the Rapid Rooter actually looks wet or shiny, it’s too much water. Try turning the top-feed off every few hours, or hand-watering the seedling at first. Too much moisture can kill!
Don’t use a humidity dome on seedlings unless it’s very dry where you live. If you do use a dome, consider keeping a vent open and watching the humidity. A young seedling doesn’t require high humidity, and they tend to get “wet feet” and stop growing in constantly wet conditions.
Now that your seedling in in the tank, it’s time to learn how to….
6.) Take Care of Hydro Seedlings
Here are tips for taking the best care of hydroponic marijuana seedlings:
These seedlings are a few weeks old, and the grower plans to move them all to the
This is a time-lapse video of a cannabis seedling sprouting and growing over 13 days.
Get Answers to Common Questions About Growing Marijuana in Hydroponics or DWC
Cannabis seedlings just getting their bearings – try to avoid moving or disturbing them until they are growing fast, with new leaves every day!
Big cannabis plants ready to switch to the flowering stage
I thought hydro plants liked it cold?
Just like in soil, cannabis plants in hydro tend to grow faster in relatively warm temperatures. This is a somewhat controversial statement because a lot of hydro growers prefer to keep their temperature lower in the grow space to help prevent root rot. In fact, there are some growers right now who are reading this and shaking their heads at me.
There’s good reason to believe that hydro plants would grow better with a cool reservoir. For example, the bad microorganisms that make root rot don’t survive well at lower temperatures. Additionally, water can physically hold more oxygen at lower temperatures, which seems like it would be great for faster plant growth. Because of this, lots of growers will AC their room to 60°F, and/or get a water chiller to cool their water reservoir to a similar temperature.
I do agree that if the temperature is above 80°F, your plant is a lot more likely to get root rot. However, I personally have not found that cool temperatures are adequate to prevent root rot. Even if the temperature is 60°F, you still need lots of bubbles and a “good bacteria” supplement like Hydroguard to prevent root rot in many cases.
I’ve seen several growers buy a water chiller and still get root rot. So I personally don’t believe cold temperatures are the best way to go to keep roots healthy.
The other reason I recommend to keep it warmer is because the plants just grow faster around 75°F in hydro. If your roots go from 60°F to 75°F, you’ll see the plants start growing faster in just a day or two, just like how plants in soil grow faster when it’s warm!
Just like in soil or coco, cannabis plants in hydro grow fastest when it’s a little warm, around 75°F!
Although there may be more oxygen dissolved in the water at lower temperatures, at least in my grow tent that apparently isn’t the limiting factor to growth, because plant growth speeds up at warmer temperatures.
I’ve found that if the grow space feels cool to you, it also feels cool to your plant most likely, and it may not be growing to its full potential. Some Sativa strains are particularly sensitive to the cold, though some Indica strains from cold climates will still thrive at lower temps.
Autopsy: Why Aren’t My Seeds Sprouting?
If your seeds still aren’t sprouting and growing properly, consider the following factors.
If there’s no germination at all…
If seeds sprout, but then stop growing…
Posted by: @charlieNice. This info is good. Do you know anything about setting up a water system, and what light we need. Filters and what-not. I want to know how set up a mass farm. Vertical farming and what not.
where are you going to grow yours?