After about 8 to 12 weeks of flowering it will be time to harvest. It is very important to harvest at the right time. The optimal time to harvest marijuana plants is when THC production has reached its maximum.
A rough guide as to when to harvest is to wait until 50%-80% of the white pistils (hairs) have turned dark (usually brown or red). But a better method of determining when to harvest is to wait until certain trichomes on the plant have matured.
Trichomes on marijuana plants that develop a resin gland at the top are a rich source of THC, and monitoring them will allow you to best judge when the plants are ready for harvesting. A better description of harvesting directions can be located
here.
Right after the plants have been harvested, they should be manicured (leaves removed from the buds), then dried and cured. Marijuana is not potent just after harvest, it is also is harsh and bad tasting. Drying will let a majority of the water in the plant evaporate quickly and curing will finish the drying process.
After the plants are cut down, some of the THC is in a non-psychoactive acidic form. Besides improving the taste, drying and curing marijuana will convert the non-psychoactive acidic compounds into psychoactive THC. A better description of drying and curing directions can be located
here.
If your marijuana is going to be stored for any amount of time, it should be put in an air tight container and be stored somewhere that is dark, dry, and cool. Remember that light, air, and heat are the things to avoid. They will degrade THC and make marijuana less potent