Most plugs are dry blocks of (usually) coco fibre. Peat plugs are an interesting alternative, as these contain some initial nutrients to help the seedling along. After fully absorbing about 500ml of moisture, or 250ml of a root booster and another 250ml water, they slowly turn into a moist, soil-like plug. Grow plugs usually have a premade hole in which to place the seed. After sticking the seed in the top of the plug, cover it lightly with a little leftover plug fibre. It takes a few days at maximum before you see the first heads pop. As soon as the roots grow out of the bottom or the side of the plug, you can stick the entire plug, complete with its seedling, into your intended medium. These plugs make germination and the initial transplant a piece of cake.
The top layer is the perfect place to germinate cannabis seeds, as it dries out faster than the soil further down the pot. This makes it easier to ensure the right level of moisture for the seed to germinate. If it gets too wet, the seeds will rot in the soil. If it stays too dry, the plant will not be triggered to emerge from its shell. Again, it’s all about finding the perfect balance between too wet and too dry.
Germination is actually a process where you activate a dry seed that is in a ‘sleeping state’. By adding water to the seed, a small root that is inside the seed-shell will want to come out in search for more water. This will make it develop into a big taproot that’ll serve as an anchor for the plant and from which more roots will sprout. Read more about root-development in this article: ‘Clones vs. Seeds: What Grows The Best Cannabis?‘
How To Germinate Cannabis Seeds in Plugs
The best known way of germinating cannabis seeds is to put them on or between wet paper towels or cotton wool. This method exists in different varieties, as it’s not so much about the paper itself, but more about the absorbency of the material. It’s very easy to make sure the ‘medium’ doesn’t get too soggy and doesn’t dry out easily. If it does dry, you can effortlessly add a few drops of water to immediately re-moisten it.
For this method, simply prepare your medium by moisturizing it, again, without soaking the soil completely. Then take your flower pots and use your finger to make a small hole about 10-15mm deep in the top layer to put the seed in. Cover the seed up loosely and top it off with a little water. Be careful not to give too much at once though! A stream of water can cause the seed to travel further down the pot where it’s too moist – and too deep to travel back up again.
Another common method of germinating cannabis seeds, and probably the most natural one, is to stick the seeds directly in their intended medium: the soil. You can do this with or without soaking it in root stimulator for a few hours first.
Even though living weed plants love (and need) a lot of light, germinating cannabis seeds thrive better in a dark environment. And just like there are different methods of growing your own cannabis, there’s also a choice in how to make your seeds sprout.
Germination is the process that brings a cannabis seed out of its hibernation period and starts the cannabis growth process. Photo by: Gina Coleman/Weedmaps
Whether you’re planning an indoor cultivation or outdoor grow, it’s best to germinate your seeds indoors. It’s easier to maintain proper temperature, light exposure, and moisture inside, and you can protect your seeds from the elements. Indoor germination, whether using soil or paper towels, will ensure your cannabis seeds have the best chance for survival.
To germinate seeds indoors, use any of the methods described above. Within a few days, you’ll have popped seeds ready to transfer to a growing medium.
Use a spray bottle to moisten the paper towels and then store the cushioned seeds between two plates, under a face-down bowl, or gently place them in a plastic bag. Maintain a temperature of about 72 degrees Fahrenheit, keeping the paper towel wrapped seeds in the dark and away from a windowsill. In two to five days, the seeds will pop inside the paper towel sandwich and emit tiny roots, ready to plant when they reach about five millimeters in length.
The paper towel method is also a common way cultivators pop their seeds. Some even use this method with cotton pads instead of paper towels, but the necessary steps are the same.