Germinating Cannabis Seeds 

Germinating, or “popping” seeds, is one of the first steps you’ll take as a cannabis grower. Germination is the process by which a plant begins to sprout and grow from a seed.

There are many advantages to starting from seed, like the large strain selection you can choose from, and the ease of online ordering. Many growers like to germinate several seeds at once, and then eliminate the weaker plants, thus ensuring hearty plants in the garden. 

Getting Started with Seeds 

Always look for mature seeds, which are dark and feel strong, versus lighter colored seeds that feel they might crack under pressure. Try to handle them as little as possible, especially during the germination process when you want to try to keep things sterile. 

Don’t be afraid to sprout several seeds at a time. It is very common for some seeds to simply never sprout, or for other seeds to be slow and take much longer to germinate. Popping multiple seeds at once gives you a greater chance of successful germination and more healthy seedlings to choose from. 

Germination Methods

There are several methods for germinating seeds, and no one method is superior. Choose a method you can attempt with confidence, and try not to be discouraged with any setbacks. Cannabis growing is deeply rewarding work where you are always learning as you go. Every round of germination is another learning process. Try several different methods and your confidence in working with cannabis seeds will grow right along with your plants.

The Wet Paper Towel Method

The classic grade school throwback method! Take a few moistened paper towels and lay them on a dish or small plate. Place your seeds an inch apart on the paper towels and cover with another moist paper towel. Create a dome by covering the seeds with an upside-down dish, and let sit by a window with lots of light so they stay warm, between 70-90°F.

Now it’s time to wait. Check on the paper towels periodically to make sure that everything is still moist. Add more water if needed, and don’t disturb the seeds. In about 3 or 4 days, you should hopefully see small taproots emerge. That taproot will become the main stem of your plant. Congratulations you have just germinated seeds! 

The Glass of Water Method

This is the easiest method for germinating seeds. Fill a small glass with water and then add your seeds. In a few days, you will see that familiar taproot shooting out of the seeds. Use tweezers to very carefully remove the seeds from the water, without breaking the taproot. Then, place in the growing medium of your choice. Be sure to keep your growing medium very moist for your budding seedlings.

Humidity Dome and Rock Wool Method

This method is my favorite. There are more steps upfront, but a far less chance of the seed’s taproot being broken after germination. For this method you will need: 

• Rockwool cubes from any gardening supply store
• A cloning tray with dome
• Low-level grow light or window with direct sunlight

To begin, I put as many cubes of rockwool in water that I need for the number of seeds I am germinating. Soak the rockwool for at least ten minutes. Next, place the rockwool into the cloning tray. Make sure not to squeeze the excess water from the rockwool as it will break the “cells” that hold water in the cube. You want these cubes to remain moist. 

Place the seed into the hole on the top of the rockwool cube and tear off a small bit of rockwool from the corner of the cube, and cover the hole with it. Fill the bottom of the tray with water and cover with the humidity dome. Place the tray under a low-level light (I use a 100 watt LED light) or in a window where it gets plenty of sun. Make sure to keep the rockwool moist and in 4-7 days you should see seedlings sprouting from the tops of the rock wool. 

The Good Ole’ Fashioned, “Throw it in Dirt” Method

Fill a 1-quart planter with your preferred growing medium. Fully saturate your growing medium with water, and then plant your seed about a half an inch deep. Place the container under a grow light or by a window and in about a week you should see a seedling breaking the surface. This “set it and forget it” method has the advantage of less handling of the taproot and therefore less chance of damage since there is no need to transplant to a growing medium. 

Transplanting Germinated Seeds

Whatever the method of germination, once you’ve got a sprouted seed it’s time to give it a home in a small 2-inch pot. Fill with the grow medium of your choice. I prefer coco coir that has been watered thoroughly. Make sure whatever growing medium you use is already wet when transplanting your sprouted seed. Poke a hole about half an inch down and use tweezers to carefully drop the seed into the hole. Cover with soil and lightly water. Keep everything moist, and in about 4-7 days you should see a seedling popping up. 

Once you have Seedlings

If you successfully sprout several seeds, it’s time to decide what to do with them. Depending on your local laws or your grow space, you will likely need to destroy any extra seedlings. 

Choose the heartiest and healthiest seedlings to continue growing. You may want to let your seedlings grow for a couple of weeks to see which plants look the best. I always look for short squat plants with large fan leaves and tight internodal spacing (the space between nodes). 

Time to Grow!

Germinating seeds for an at-home cannabis grow can be a little overwhelming, but with patience and gentle hands, you’ll soon be on your way to a bountiful grow. Happy gardening!