Killing an indoor herb plant during the winter is almost like a rite of passage for gardeners. So don't worry if your rosemary croaked in the past. The problem is most likely your house, not you. Low indoor humidity and light levels have knocked off more than a few indoor herbs, especially when combined with overzealous watering. Experts often recommend growing herbs under artificial light, but who wants a shop light hanging in their living room? So we came up with the perfect compromise: concealing a fluorescent light inside a bookcase. This technique allows you to give your herbs plenty of light, and it's a pretty handy place to store, say, your back issues of Organic Gardening!
What you'll need:
1. Drill a hole in the back of the case near the top for the light fixture's cord.
2. Place the bookcase upside down on the floor, fit the light fixture into the bookcase, and attach it to the top with screws.
3. Turn the case upright and put it in the desired location. Fill a shallow tray with pebbles or crushed glass and set your herb containers onto the tray. Adjust the top shelf so that the herbs will be about 1 or 2 inches below the light. Place the herbs under the light fixture and fill the tray of pebbles with water, which will slowly evaporate and improve the humidity around your plants.
4. Plug the light into the timer. Set the timer so that the herbs receive 14 hours of light and 10 hours of darkness each day. Allow the herbs' soil to nearly dry between waterings and hold off on fertilizer until the plant begins to grow vigorously in spring.