Soil test - increase calcium with affecting pH?
I've read that your calcium/magnesium ratio should be 7, and that low calcium can cause of a lot of different weeds (we had a ton of dandelions a few weeks ago). I got my soils tests back a few weeks ago, and my Ca/Mg ratio is 5 in the back yard and 4 in the front, but I think my pH was pretty good - 6.9 and 6.7. I'd like to add some calcium without affecting the pH, what would be a good source for that? Gypsum?
On the other hand, my test listed my pH buffer at 6.35, and my soil is rather clayey. Maybe calcitic limestone would be ok anyway?