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how to germinate cannabis seeds in rockwool

How to germinate cannabis seeds in rockwool

the paper towel method ALWAYS works. IMO

germinate them what ever method you prefer to use,

i would have soaked mine over night first 75 percent of time is split the next day

Charlie Green

I don’t know where the paper towel method started, I only know that it has been around far too long. I first learned of it over 30 years ago. It’s hogwash. does it work? Most of the time, but why risk handling a delicate seed and it’s new born tap root when you can simply place the seed in any moist medium and have it germinate? If the seed germinates in a paper towel, which surely can’t sustain the seed, won’t it surely germinate in moist rockwool?

i have a Hydro set up also so i have been starting seedlings in rockwool for years.

Well-Known Member

i have a Hydro set up also so i have been starting seedlings in rockwool for years.

germinate them them move them to the rock wool cubes

How to germinate cannabis seeds in rockwool

Since rockwool cubes naturally have a very high pH, you need to offset this by lowering the pH of your watering solution. This is the most critical part of growing pot seeds in rockwool.

What is the proper pH when watering rockwool cubes for cannabis seeds?

It’s easy to learn how to start seeds in rockwool cubes in a few simple steps. We’ll show you the best way to start seeds in rockwool cubes, how to prepare rockwool, when to start feeding seedlings, the best nutrients for rockwool, lighting for growing marijuana seeds, and when to transplant rockwool seedlings. This advice also works if you’re looking to start seeds in rockwool that aren’t weed seeds, the techniques are the same.

How to start seeds in rockwool cubes

Durolux makes a two-foot T5 grow light with 4 bulbs for about the same price as the Vivosun 2 bulb T5.

How to germinate cannabis seeds in rockwool

With the rockwool cubes properly pH adjusted to 6.1 I placed 5 rockwool cubes into the solution for 60 minutes. As for the exact time to soak I found conflicting advice. Some guides said to soak for a whole day while others said 15 minutes. I took a gamble with 60 minutes.

Here’s a video of me inserting one seed into a cube:

Now that the cubes were properly prepared it was time to insert the marijuana seeds and store them in an ideal sprouting environment.

Remove Cubes and Let Drain

The downside to using rockwool is the need to prepare the cubes before you insert your seeds. Rockwool has a pH of 7.8 and plants like a pH range of 5.5 – 6.8. If you were to simply insert the seeds into rockwool soaked in regular water the pH would be too high and will cause the seed not to sprout or kill the seed.

Congrats! If you succeeded in getting your cannabis seeds to sprout you are now on your way to growing a healthy marijuana plant.

Inserting the Cannabis Seeds

After acquiring growing equipment and cannabis seeds I now had everything I needed to start growing marijuana. The first major step in this process is germinating the seeds or getting the plant to sprout from the seed.

To prevent this from happening you use an acid like pH Down (phosphoric acid) which can bring down the pH level of the water you plan to soak your cubes in. This is why it was important to buy a reliable pH meter.