Indoor basil plants need lots of light, a good amount of watering and ongoing pruning to remain healthy. Basil plants bloom in the summer and flower buds must be removed as they appear to prevent seeding, which eventually kills it. If you are starting with seeds, allow basil seedlings to grow for two weeks then transplant them into a 4-inch pot so they have room to grow.
Place indoor basil plants near a window where they can soak up plenty of sunlight. Alternatively, you can use fluorescent lighting, but be sure to keep the light bulb at least 2-inches or more away from leaves. Keep basil under artificial fluorescent light for 12 hours for best results. Its roots require loose soil that is well drained at all times, and it should never be over watered. However, basil needs adequate moisture, because it can easily dry out.
Water your basil plant enough to keep its soil moist, and you can give its leaves a daily misting of water. Feed it once a week with a weak formula plant fertilizer. Prevent mildew growth by periodically running a fan near the plant to circulate air. If mealy bugs or spider mites appear on basil plants, don't use pesticides. Instead, mist the plant with a mixture of water and dishwashing liquid or insecticidal soap.