Basil is one of the easier herbs to grow indoors, providing you can give it enough light. As with many other herbs, basil is a true sun-lover—give it four hours of light a day, and it will thrive. Alternatively, basil does exceptionally well under lights also, and with a regular compact fluorescent bulb, you can grow enough basil to keep your kitchen stocked all year round.
Light: At least four hours of full sun. If you're using fluorescent bulbs, keep them on for 12 hours, with the lights about 2-4" away from the plant. Don't let leaves touch the bulbs to prevent burning.
Water: Keep regularly moist. Water at first sign of wilting. Mist regularly.
Temperature: Warm (around 70ºF).
Soil: Loose, well-drained potting mix.
Fertilizer: During growing period, use weak liquid fertilizer weekly.
Basil starts readily from seed (also under lights), so you can experiment with all different types. Most basil varieties germinate in about 5 days at 80º. Lower temperatures will increase germination time.
Most people eat their basil before they can repot it! If you're growing from seed, step up seedlings after two weeks into a 4" pot, which will likely be its final home. Trim after the newly repotted plant is established to encourage more leaves. Basil responds well to pruning, but don't expect indoor plants to get quite as large.
There are dozens of types of basil, including lemon basil, Thai basil, purple, and many others. The "typical" basil is Genovese basil, which has bright green leaves and small white flowers.
Basil is a uniquely rewarding plant to grow—it's relatively pest and disease free, and it's fragrant and delicious. Basil responds well to pruning and topping, so feel free to use leaves as soon as the plant is established and branched out. Basil's taste changes throughout its life, becoming stronger as the plant flowers. If you see flower buds forming (about 75 days after planting), snip them off and prolong the plant's vegetative phase. Basil that has flowered can still be eaten, but it will be bitter.