Plant seeds so that the white root faces downward, about a knuckle deep into your growing medium. The top of the seed should be just below the surface of your growing medium. It can take anywhere from a couple of hours to a couple of days before you see the young seedling emerge from the soil or growing medium.
If your marijuana seedling hasn’t sprouted from the soil within 10 days after being placed root-down, it probably isn’t going to make it 🙁 Even with the best practices and the best seeds, you will occasionally lose a seed. You can use them before you transfer your seedlings to their final container. The Rapid Rooter should be cut open lengthwise if you plan on using them for germinated seeds. Gently place the germinated seed inside, root down. Place the seed close to the surface so it doesn’t have far to go. Sometimes you’ll have a taproot that is curved or bent. Open the Rapid Rooter you split, and lay the germinated seed down gently. The seed and root will naturally lay on the flattest side.
Slowly close the Rapid Rooter, and you’ll see that the bent parts of the root will end up in the “crack” of the Rapid Rooter from where you cut to split it open from the side. After closing a Rapid Rooter, it’s hard to tell it’s been opened. The texture of Rapid Rooters causes the seeds to stay in place and not “fall down” further into the hole once you’ve got it closed. Sometimes the shell can get stuck on the seedling, but it will often fall off on its own. If it seems really stuck, you can help the seedling by gently removing it. Within the first week of germinating seeds, you will notice that some seeds germinate right away and others take a little bit longer. This can be caused by a lot of things, from the age of the seed (old seeds have worse germination rates and tend to take longer) to simple chance. The amount of time does not necessarily have anything to do with how healthy your plant will be in the long run. Once your seeds are safely planted, you can turn on your grow light. The heat from the lamp improves germination rates, and the light can help your new cannabis seedlings open their first set of leaves. In fact, the first set of leaves will often stay yellow until they get light. If you will be transplanting your seedlings again, avoid transplanting until they are well established and have a couple of sets of leaves (nodes). Some growers will plant seedlings in a growing medium in a solo cup or peat pot, so they can just cut away the cup for easy transplanting. When you move seedlings around a lot, it stresses them out and potentially stunts their growth. So try to plan from the beginning so that you move your seedlings around as little as possible. once they get bigger, they are a lot more hardy and can stand a lot more stress and movement. Here are some pictures to give you an idea of the timeline to expect. Sprouted seeds planted in Hydrofarm pellets and placed on soil. If you want, you can put bottles on top to help retain extra humidity (like a cheap humidity dome). It’s a steady 85 degrees F in there, no idea about the humidity in the bottles. During the first few weeks of a young marijuana plant’s life, you have to be careful. Marijuana seedlings, especially seeds from some of the most potent strains, tend to be a bit delicate. Seedlings definitely won’t be able to withstand full-strength grow lights or nutrients. They need to have a moist environment, but also can easily be drowned or overwatered. If you’re planting in soil, start with a balanced potting soil that doesn’t contain extra nutrients.
I recommend Happy Frog potting soil mix for young cannabis seedlings, but any plain potting mix from your local garden store will do. Never use Miracle-Gro soil or any soil that has “time-released” nutrients already mixed in. After your plants have grown a few sets of leaves, you can transfer them to a stronger potting mix that contains higher levels of nutrients like Fox Farms Ocean Forest soil, or you can start supplementing with cannabis soil nutrients. Learn how to mix up your own super soil so it has all the nutrients your cannabis plants will need! If you’re planting in coco coir, a soilless medium, or hydroponics, only add cannabis nutrients at seedling strength, or 1/4 the regular strength, until your plants have grown a few sets of leaves. Then you can slowly start working your way up to full strength nutrient levels. You’re trying to give young plants a very small dose of nutrients at first.
However, even with young marijuana seedlings, the pH of your water and growing medium is important. Some growers get lucky and happen to have water with the right pH, but if you’re noticing deficiencies and problems with your seedlings, definitely take the time to understand about marijuana root pH and how it affects the plant’s overall health.