My team and I (Taylor, Heidi, and Jonna) wanted to see if volcanic ash would act as fertilizer for our radish seeds. what we did is we had seven cups and we filled up each cup with the same amount of soil then we marked each cup as none, i ml, 2 ml, etc. all the way to 6 ml. of ash. we would water them each 20 ml. of water. near the end of the expirement the cup with 6 ml. of water. without soil the plants have nothing to anchor down in to hold them still from the wind. the soil holds in nutrients left over from surrounding dead plants.
Jansen, Jim. "Why Do Plants Need Soil & Water?" EHow. Demand Media, 12 May 2010. Web. 01 May 2012. <[LINK]