Oh, TIKilty, thanks so much for your advice. We DO have clay soil! I was going to put my experiments in pots, but I might have to go for a ground plot, as I might run out of pots!...in which case, it would be critical to do as you suggest!
I just read your suggestion to Darlin, who definitely ratifies it!
After the weekend, contct your local highway department and see if they have any composted leaves , or mulch for free !
Also , check with any of the tree removal companies in the area. The only leaves /mulch to avoid is walnut (julgone).
Oak leaves are slow to break down , but a lawnmower or grass trimmer can do wonders to speed up the process.
When in doubt , always go for the "free Stuff ", especially arround the town barns , or town dump, or tree trimmers lot.