Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
Cannabis used for hemp production has been selected for other traits, including a low THC content, so as to comply with the 2018 Farm Bill. Consequently, many varieties of hemp produce significant quantities of CBD.
You might also find a mature seed that has been physically damaged through poor handling, like rough trimming. In those cases, it probably isn’t worth the effort to try and germinate the seed.
If cannabis is legal in your state, you can buy seeds or clones from a local dispensary, or online through various seed banks.
Keep a close eye on the temperature and moisture level of the soil to keep the seed happy. It’s very delicate at this stage. Use a spray bottle to water it—over-watering can suffocate and kill the delicate sprout.
As mentioned above, you can skip the processing of sexing weed plants by growing with feminized seeds or clones.
Ask yourself a few questions to decide if it’s worth the time and energy to grow the seed.
We like to use seedling pellets that are made of a mix of compressed peat moss and coco husk. To expand, soak it in water for 10 minutes. Once your seedling pellet has absorbed enough water and has expanded to its maximum size, drain off any excess water. The growing medium should be like a damp sponge that would not leave streaks on the table. Dig a small hole about 1/4 in deep for your seed. Use a spoon to lift the seed out of its bath. If it has popped out a taproot be careful not to damage it. Gently place the seed into the hole and lightly cover it with dirt from the pellet. Now that you have started the germination process, your seedling will come above ground within two weeks. The older the seed, the longer it takes for it to germinate.
For young plants, it’s best to use bottled water as it has no chlorine added. If using tap water, let it sit for 24 hours before watering to dissipate any chlorine. Chlorine can also be eliminated by boiling for 20 minutes. Under normal conditions, after soaking your seedling pellet, it should contain all the moisture your plant needs before it comes above ground. As it grows, it will only need about a shot glass worth of water at most per week to keep the medium damp. Seedlings don’t drink a lot of water, which makes sense given their size. Your plant will do better in a growing medium which is damp. Overwatering is just as deadly as drying out.
Raising a seedling, however, requires some patience, gentle hands, and a smidgen of luck. Thankfully pot seeds are remarkably vigorous because they are what’s called endosperm seeds, which means they have almost pre-formed cotyledon leaves before you even add water. Below is a brief guide on the techniques we have found yield the most success when starting seeds and raising your seedling to a healthy plant ready for transplanting.
2) Planting your seed
Our favorite thing about starting from a seed, rather than a clone, is that you get to see the full life cycle and enjoy a plant that is unique, just like you. An entirely new genetic makeup will enter the world for the first time, and if you’re lucky, something remarkable might be born.
To accelerate germination, you are going to want to soak your seed in a small container with lukewarm water and place it in a dark and warm place for 12-24 hours, but no longer. By drenching the seed, it absorbs the water thoroughly, activating the germination process. Doing this also helps to loosen the shell as it becomes a little softer making it easier for the embryo to crack it open. When your seed sinks to the bottom it is ready to be planted, and sometimes the seed will pop out a small taproot. A seed can still be planted though if it does not sink.
Seedlings require a medium amount of light in which it has enough to grow but not too much light that it gets burned. Leaving your seedling in direct sunlight will cause the leaves to curl, while too little light will cause the seedling to stretch. If growing outside, seedlings want to see a direct light source to stop them stretching. If inside, a sunny windowsill with more than half a day of sunlight works wonders. Otherwise, 18 in away from a growing light works excellently. Your seedling should not stretch more than 6 in at most. We’ll cover lighting in more depth in a later blog.
Perhaps the most exciting stage, your baby will typically come above ground in 1-2 weeks. As your seedling comes above the soil, its shell might take a few days to fall off. It’s best to leave it alone, nature has the job covered. If it does not come above ground after about two weeks, the chance of success is dramatically reduced, and it’s best to try again. Even the best seeds have an 85% germination rate. When your seedling comes above ground, it is going to want to see a direct light source.
If you’re growing outdoors in a climate that’s hot and sunny, heat stress could be a problem. Ensure that your plants have some access to shade, especially around midday. Put up some shading or choose a spot with some natural shade to protect your plants from the heat.
As an alternative to plastic pots, you can also use fabric pots (smart pots) or air pots. If you want to learn more about the different pots used to grow cannabis, check our article on the subject.
Seedlings are very sensitive and do not take kindly to growing mistakes like improper humidity and moisture levels. Both could spell the premature end for your seedlings.
10. HARVESTING TOO EARLY OR TOO LATE
Excessive moisture is also bad news for seedlings. When humidity levels are too high or when you overwater your seedlings, this can lead to the dreaded damping off, a deadly fungal disease. Seedlings will become weak and tip over, and there is nothing you can do to save them. Avoid extremely high humidity and overwatering, and make sure to use a sterile medium for germination.
Overwatering is much worse than occasional underwatering, as plants can almost always recover from slightly dry conditions. But when they’re constantly overwatered, this deprives the roots of oxygen and will lead to all kinds of troubles like fungus and root rot. Always allow the soil to dry out between waterings. Less frequent watering is better than overdoing it!
If you’re growing outdoors, air circulation shouldn’t be a problem; but then, there are other things to watch out for. For one, you’ll want to protect your plants from thieves. You can do so by planting companion species to hide your crop and mask the smell. You can also select cannabis strains that naturally remain short and hidden from view. Find out more about stealthy outdoor grows in our blog on how to protect your cannabis plants from thieves.
Correct pH levels