Updated: Dec 8, 2020
First off, information about storing marijuana seeds is also relevant and important for growers. It's best to keep them cool, dark and dry; for example in the fridge with some silica packets or rice. All seeds are different, but, in general, cannabis seeds lose efficacy after a year or so. That being said, some could sprout even after a period of several years. When you’re ready to grow your outdoor weed plant, expose the seeds to light and moisture. The exposure to light and water will activate a series of hormones within the seed and kickstart the growth process. A single root grows down and splits open the outer shell of your seed, and then you can plant it. The root reaches downward into the soil in search of water and nutrients. At the same time (or just after), a green stalk will shoot upward and two initial cotyledon leaves will appear.
As the seedling continues to grow, it will continue to break apart the seed coat that was protecting it. The root systems at the base of the plant will begin to develop, and leaves will begin to spread out and grow at the top of the plant. Soon new leaves will grow and the plant will enter it’s first true growth cycle.
After about 3-7 days of initial growth, a healthy plant should have grown into a seedling. This stage of growth is defined by a plant that has begun to develop a stable root system, as well as initial growth of “true leaves”, that is, leaves which exhibit the same form and characteristics as mature cannabis leaves. The perfect heat during this stage is 77 degrees. Also, humidity is important, just like the time of germination. Nutrients can burn the cannabis seedlings so therefore few are necessary. White light (18 hours per day) is needed from the instant you see the cotyledons, as well as some fertilizer with nitrogen (like grow booster), a temperature between 68- 77 degrees and humidity of approximately 60%.
Vegetative stage This is when your cannabis plant really comes into its own, producing the sort of big jagged leaves you’ve been waiting for. The plant produces so much more foliage because it’s now capable of absorbing and processing a much higher amount of carbon dioxide and other nutrients. During the vegetative stage of growth, the roots will continue to expand and the plant will grow taller. This is the point at which people say you can “watch your plant grow”. A healthy cannabis plant can grow up to 2 inches in a single day!
The vegetative stage should take a minimum of 2 weeks. After that, you can force flowering or it's okay if flowering starts. The temperature should be between 68- 77 degrees, with dampness from 50% to 70%, perpetual white light of at least eighteen hours a day and additional fertilizer with nitrogen.
Flowering stage The end stage for the cannabis plant is the one that’s most important for growers and cultivators (and eventual beneficiaries of the harvest). The flowering stage occurs after reduced light exposure, and when a plant becomes sexually mature and ready to spread its genes around.
About 10 days before the plant becomes mature you should stop to fertilize the cannabis. You can identify maturity when the buds get an even thicker structure, are more resinous and more odoriferous. The pistils turn brown, the large leaves turn yellow in large numbers, the buds expand and gain weight and the development of calyces slows down. Depending on the type of cannabis and on your taste, you can start to harvest now. While you want your plants to flower for a good amount of time, it is definitely possible to let cannabis go for too long. In this over-mature phase, the cannabis plant will stop to have medicinal value because it deteriorates. Enjoy your outdoor weed garden.