That recommendation of 40 lbs of lime sure does seem like a lot for a 600 sq. ft. garden area. Especially this close in attempting to plant the gardening. I think I may just try about 20 lbs and add the rest in the fall.
I am not so sure. Garden Lime is crushed limestone, rock, powdered rock. That’s gonna be heavy. I suspect 40 pounds is about 1-1/2 cubic feet or so. That spread over a 20x30 area is not that much.
I did read a cautionary note that said not to add lime and fertilizer at the same time. Apparently it can cause a chemical reaction that is not desirable.