Follow these tips to keep your indoor plants healthy and productive:
1. You must prevent your herbs' roots from rotting if you want productive plants. Repot your herbs with a well-draining soil mix. Specialty cactus-growing mediums work great because they are designed to drain extremely well, but you can also mix sand into a soilless medium using a 1-to-4 ratio. Make sure you allow the soil to dry down to about your second knuckle between waterings. Fertilize your plants once a month with diluted fish fertilizer (don't worry, the smell goes away quickly, I promise).
2. Herbs don't like soggy soil, but they prefer humid air. Solve this paradoxical problem by setting your pots on a tray of pebbles. Then fill the tray with water, making sure that the bottoms of the pots don't come in contact with the water. Viol! Instant humidity. You can also mist them daily.
3. Place your tray of herbs in a south-facing window. Herbs need at least 5 hours of bright, full sunshine a day to stay healthy, and sometimes the low winter light just isn't enough. For the best results, place your herbs under fluorescent lights for 14 hours a day. Keep the lights 6 to 8 inches away from the tops of the plants. Basil, chives, oregano, rosemary, sage, and parsley can all be grown indoors.