Ebb and flow hydroponic systems are a great way to get started in hydroponics and make a wonderful educational project for children. Not to mention you can grow yummy food easily and inexpensively in your own home year round! A system like the one shown here is the perfect size for a kitchen herb garden.
A basic ebb and flow hydroponic system consists of a growing bed, porous growth media, a nutrient reservoir, pump and a timer. The system works by periodically flooding the growing bed with a nutrient solution and then allowing the nutrient solution to drain from the bottom of the growing bed. As the nutrient solution drains, oxygen is drawn into the growth media from the top. Because the growth media is porous, it retains moisture and nutrients, and allows oxygen to get to the roots of the plants.
Supplemental lighting is necessary if you will be growing plants indoors. Specialty grow lights are available but you can achieve good results using common light fixtures and 100 watt equivalent "daylight" compact fluorescent bulbs available at most home stores. Generally, I like to locate my hydroponic system near a window to take advantage of natural light and add one or two supplemental light sources as needed. Just make sure that you can adjust the height of the light fixture so that it can be easily re-positioned as the plants grow.