A strain is a specific species of cannabis type, often developed through plant breeding. When it comes to strains, you're primarily choosing between indicas, sativas, or hybrids of the two. Strains come with some pretty interesting names that usually indicate the other strains they've been bred from. Indicas tend to have a more sedative effect for sleep, while sativas tend to be invigorating and enhance creativity. Hybrids provide a combo of these two in a variety of ratios.