thanks for all of the responses. we should ask Dave about it.
do you think there should be just one soil type per plant, as in "preferred soil type = sand"?
I'm thinking that there should be two database fields. One would be "preferred soil type". the other would be "acceptable soil types". So, for example, if a plant preferred sand, but could grow in loam, then the acceptable types would be sand and loam. I would think having those two database fields would give gardeners everything they need to make informed decisions. do you agree?
once these fields are available in the database Dave could run some sort of promotion to try to get everyone to help populate them.