Soil Test in Tomato Bed: Question
I've decided to do what I've never done but always intended to do, namely have my soil tested by the University of Minnesota agricultural extension dept. They have a home vegetable garden test for $15, which evaluates soil fertility (NPK), pH, and percentage of organic matter. For $5 extra, they'll also do a "soluble salt test," which analyzes for "problems due to excessive salts or fertilizer materials." Any of you with experience here: Do you think the soluble salts test would be worth doing?
I'm growing 90 tomatoes this year, 28 in-ground. It's soil from this bed I'll be sending in. The proximate reason for this is that, while healthy, these 28 plants seem to be lagging behind (based mainly on height) plants I gave to friends which have grown a good foot higher, though the fact that they were planted out 7 days earlier than mine may help to account for the difference. I grow tomatoes in this bed year after year, amending the soil with fresh compost each year (and this year with additional topsoil from raised beds elsewhere on my property). I don't really know if anything is "wrong," but I assume the soil test will help me assess that.
Thanks in advance for any advice or suggestions.