Hi, Peter: This is tough to answer without knowing what your cross-pollinator is and where you are, but certainly a pH of 6.5 should be fine. Do some research and make sure that you have a cross-pollinator that works well with Rainier (Bing is a good one). Make sure that you are pruning/trimming the trees (in late summer) such that you are encouraging one main trunk stock with fruiting branches coming off it, rather than allowing larger branches to develop. Mulch your trees with 1 inch of 50/50 garden compost and well-rotted manure, refreshing this each spring. The other thing is to fertilize your trees in late summer with 1 to 2 pounds per tree of 10-10-10 fertilizer scratched into the mulch and watered well. That’s it, though: Overfertilizing is as bad as under-. Good luck!
Hi, Peter: This is tough to answer without knowing what your cross-pollinator is and where you are, but certainly a pH of 6.5 should be fine. Do some research and make sure that you have a cross-pollinator that works well with Rainier (Bing is a good one). Make sure that you are pruning/trimming the trees (in late summer) such that you are encouraging one main trunk stock with fruiting branches coming off it, rather than allowing larger branches to develop. Mulch your trees with 1 inch of 50/50 garden compost and well-rotted manure, refreshing this each spring. The other thing is to fertilize your trees in late summer with 1 to 2 pounds per tree of 10-10-10 fertilizer scratched into the mulch and watered well. That’s it, though: Overfertilizing is as bad as under-. Good luck!