Don't worry - industrial hemp is not going to destroy your grow..... Back to Biology 101: THE GENUS CANNABIS The genus Cannabis contains three species: Sativa, Indica and Ruderalis There are many, many subspecies, strains and hybrids. Marijuana is defined a cannabis plant genetically bred to produce HIGH THC LEVELS. Hemp is defined as a cannabis variety genetically bred to produce either fiber or seeds or both and VERY LOW THC LEVELS. All species, subspecies, strains and hybrids of Cannabis will cross pollinate each other like crazy. A huge field of Hemp will cast its pollin far and wide dispersed by the wind to the far corners of the planet. THE POLLINATION RESULT Cannabis plants (marijuana and hemp) follow the same basic rules as all flowering plants which rely upon a sexual pollination of the ovum process for reproduction via seed production. Pollination by an undesired strain DOES NOT AFFECT THE CHARACTERISTICS OF THE PLANT BEING POLLINATED - THE NEW GENETIC CHARACTERISTICS SHOW UP IN NEW PLANTS GROWN FROM THE RESULTANT SEEDS - the hybrids. So a clone from a desired plant will not be affected by pollinization by an undesired strain. The result of the desireable plant being grown will not be affected. Only in plants grown from the seeds will the new genetic characteristics show up. So, not to worry, fields of golden hemp in your neighborhood will not ruin your grow. The only problem is if you wish to grow to produce seeds for your next crop. Then you do have to study well the processes of isolation and manual polinization, which is both a science and a fine art. If you start your plants from certified pure seed sources or by cloning from a plant with desired characteristics, you are all set. Here are two links to help: Wikipedia - Cannabis Cannabis - Wikipedia, the free encyclopedia Gametec - What happens if you cross hemp and marijuana? What happens when you cross hemp and marijuana?