Considering the fact that hemp and marijuana are members of the cannabis family, a big difference is the density of the psychoactive component Tetrahydrocannabinol or in short THC.
Marijuana usually contains 5-20% THC, and some stains that are genetically selected reach up to 35% or even more.
Hemp has a very low percentage of THC, usually under 0.3% and in some strains, there is no psycho active substance, this means it can’t induce a psychoactive effect. Hemp is developing a multibillion dollar business, producing health products, construction materials, paper, biofuel, raw oil and fiber.
Marijuana looks slightly different from hemp, if you put hemp and marijuana aside you will notice that the hemp leaves are skinnier and concentrated to the top of the plant, just a couple of branches and leaves are below the top part, also hemp is taller (up to 21 feet). Marijuana has considerable bigger buds and the leaves share is broader. In contrast to hemp, you can observe that marijuana is a short small bush with bigger buds.
Unlike marijuana, hemp is more resistant to cold climate, making it possible to grow even in northern countries. Hemp has a growth cycle of 100 to 120 days, and can be grown closely together (as close as 3-5 inch from each apart) and can be cultivated on large, multi-acre fields.
Marijuana requires almost tropical conditions, in other words a warm and humid atmosphere and it can’t be planted too close to each other, typically 5 feet from each other. Medical marijuana can’t be planted with hemp together or even closely because the hemp pollen will interact with marijuana and it will dilute the psychoactive effects.