A seed has germinated once the seed splits and a single sprout appears. The sprout is the taproot, which will become the main stem of the plant, and seeing it is a sign of successful germination.
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
As interest in CBD as a medicine has grown, many breeders have crossed high-CBD hemp with cannabis. These strains have little or no THC, 1:1 ratios of THC and CBD, or some have a high-THC content along with significant amounts of CBD (3% or more).
The main drawback to growing from seed is there is no guarantee as to what you’ll end up with—if you buy a regular pack of cannabis seeds, it will be a mix of males and females. You’ll need to sex them out (more below) to identify the males and get rid of them, because you don’t want your females producing seeds.
Feminized cannabis seeds will produce only female plants for getting buds, so there is no need to remove males or worry about female plants getting pollinated. Feminized seeds are produced by causing the monoecious condition in a female cannabis plant—the resulting seeds are nearly identical to the self-pollinated female parent, as only one set of genes is present.
Once you see the taproot, it’s time to transfer your germinated seed into its growing medium, such as soil.
To create a dark, protected space, take another plate and flip it over to cover the seeds, like a dome.
A shallow flat or planter with a heat pad underneath may require daily watering, while a deep, 1-gallon (3.8 liter) pot will need watering every three days or more. A properly watered flat of rockwool cubes needs water every three to five days when sprouting seeds.
When the growing medium’s surface is dry (0.25 inches [1 cm] deep), it is time to water. Remember, there are few roots to absorb the water early in life and they are very delicate.
6) In a few days, seeds will sprout. Once the germinating cannabis seeds have sprouted and each seed’s white rootlet is visible, use tweezers to carefully pick up the fragile, germinated seeds and plant them. Do not wait for the white rootlets to grow more than 0.25 inches (1 cm) before planting, or growth could slow. Plant each germinated seed with the white root tip pointing downward. Take care not to expose the tender rootlet to prolonged light and air. Cover germinated seeds with 0.25 to 0.5 inches (1-2 cm) of fine, moist planting medium.
Other Tips for Germinating Cannabis Seeds
1) Soak seeds overnight in a glass of plain water. They may float on the surface at first but should sink to the bottom in a few minutes. Make sure seeds get good and wet so that water penetrates the outer shell and growth is activated. Do not let seeds soak for more than 24 hours, or they might get too wet, suffer oxygen deprivation and subsequently rot.
3) Drain the water from the dinner plate by tipping it to the side.
Over and under-watering are the biggest obstacles most gardeners face when germinating seeds and growing seedlings. Keep the soil uniformly moist but not waterlogged. Do not let the growing medium’s surface dry for long. Setting root cubes or planting flats on a grate allows good drainage.