Crystal Soil® is a unique and fascinating growth medium for plants. This remarkable hydro-gel is designed to store water and plant nutrients and to release them as required by the plant. Students will be able to observe plant roots as they develop and grow. Brightly colored Crystal Soil requires no fertilizer and only needs to be watered only once every 3–4 weeks! Five colors available. The 2.5-ounce package is concentrated—when water is added, it expands to a full quart.