|MadSci Network: Agricultural Sciences|
Most definitely, plants can grow without soil. Some plants grow without soil by nature. Epiphytes are plants that grow on other plants. Spanish moss and many orchids are examples of epiphytes. There are also parasitic plants, such as mistletoe, that grow without soil. Even plants that normally grow in soil can be grown without soil if given proper care.
Soils do several things that plants need to grow. Soils have water, nutrients, and oxygen that roots can use. Soils also give physical support to plants. If we find other ways to make sure that plant roots can get the water, nutrients, and oxygen that plants need to grow, and physical support, then plants can grow without soil.
Many vegetable growers and scientists use hydroponic systems to grow plants without soil. In a hydroponic system, plant roots are bathed in an aerated nutrient solution, with strings or styrofoam blocks supporting the stems. A special form of hydroponic culture, called a nutrient film, is being tested to grow plants on space stations.
If you would like to know more about hydroponic and other agriculture without soil, try the following web sites:
http:// www.interurban.com/hydroponics/index.html - a primer on hydroponics
http:// atlas.ksc.nasa.gov/celss/plant/crops.htm - page down to see some neat photos of plants growing in hydroponic systems for space research
http://www.usu.edu/~cpl/ hydroponics.html - see their links page
http://www.hydroponics.com - one of many companies selling hydroponic systems
Try the links in the MadSci Library for more information on Agricultural Sciences.