Basil is a tender annual, meaning it doesn't tolerate cold temperature, nor will it survive Colorado's winter. Start basil seeds indoors in April, then transplant outdoors after all frost danger has passed (usually May 20.) Rich, fertile soil is the key to a bountiful crop of basil. Amend your soil with organic compost before planting. Use an organic fertilizer with every watering. Keep the soil moist, like a wrung-out sponge. Too much moisture fluctuation in the soil can make leaves bitter. If you're unsure when to water, get your hands dirty! Dig your fingers into the soil a cou Basil prefers full sun (6-8 hours,) but will tolerate a little afternoon shade. As it begins to grow, pinch it back periodically to keep the plant short and bushy. It is a "pick and come again" plant, meaning you harvest several leaves at a time, but not enough to weaken the plant. Don't allow the plant to flower, or leaves will turn slightly bitter.
Fragrant herbs aren't usually a favorite of insects, but watch for aphids, whiteflies or spidermites. You can remove these small insects with a blast of water, or use an organic pesticide, like neem oil.