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how long do cannabis seeds take to germinate in rockwool

If they’ve been moist that long and haven’t germinated, they’re most likely not going to.

Be careful to control the seed zone temperature when using a seedling heat mat.

As a hydroponics marijuana grower, you need total control over how your plants absorb water, oxygen, and hydroponics nutrients. Fact is, what you choose as the environment for your cannabis…

Don’t Drown Your Cannabis Seeds

If the media is too wet, seeds might rot or drown.

Your marijuana plants breathe out oxygen through their leaves, while intaking oxygen from their root zone. But many cannabis growers aren’t providing enough root zone dissolved oxygen. Their plants’ roots…

Such methods force you to handle your seeds when they’ve just sprouted.

Rather than using the paper towel or submerse in water methods, this method we’ve given you to germinate marijuana seeds is direct, easy, and doesn’t require you to handle, transplant, and possibly damage a sprouted marijuana seed.

This is by far the best method to germinate weed seeds.

Options for starter cubes are seemingly endless, but the majority are made of either rockwool or peat.

Best Way To Germinate Weed Seeds

Step 1: Place a folded wet paper towel into a plastic container, or on a plate.

Step 2: Place your seeds on the paper towel with adequate space between them. Cover the seeds with another folded wet paper towel.

If you put more than one seed in your cube (just in case one didn’t make it), than you probably have several seeds sprouting up in each cube at the end of

They should look like this:

On top of that, Rockwool is like asbestos, you don’t want to be squeezing it or breathing it or generally touching it any more than you need to. Here is a good article on some of the health concerns of Rockwool. I use it because it is what works best, but be cognizant to the fact that it is a potentially dangerous substance to be making contact with so don’t do anything more than you need to with it.

Here is what it should look like:

Important: Do not let the PH of the water go below 5. A Ph this low will damage the fibers of the Rockwool Cube

Now that we have the Ph adjusted water, it’s time to stabilize and hydrate the Rockwool cubes in it. Insert the Rockwool Cubes into your container and let them soak for roughly 1 hour. Once the hour is up, the cubes will be big and fat with water. Take them out of the bowl of water and put them somewhere you don’t mind getting a little wet. Save the remaining water for step 3.

Get a bowl or some other container that is big enough to fill with water and have room left for your Rockwool cubes. Your average salad bowl will work fine for 3 Rockwool cubes, if you are planning on doing more than you will need a larger container.

Using either a PH test kit or a Ph meter, determine the Ph of the water. Water comes out pretty alkaline, usually around 7.4, so you will need to acidify it a little bit to bring that Ph down to the desired level. Aim for as close to a Ph of 5.5-6 as you can get.

About 2-3 weeks after germinating, you are ready to transplant these babies into the hydroponic system of your choice. A good rule of thumb to go by is that you want to transplant them once the first roots begin poking out of the Rockwool cube. Don’t wait too long though, as eventually the roots will begin tangling around the cube since it is their only source of water. You want to catch them right as they pop out, so that when you transfer them into your hydro system the roots will grow down into the system, and not just try to feed off the Rockwool cube alone.