yoderjac
5 year old buck +
I have about a dozen Honeycrisp trees. Those on M7 or G30 rootstock do not seem to grow as well as those on MM111 or M106 rootstock in my sandy soil, even when they seem to get enough water. Iron chlorosis (the yellowing of the leaves) is more prevalent in the smaller rootstocks. Jap Beetles love them all, of course. Does anyone have the same problems?
First, let me say my experience with apples is limited and I have no experience with Iron chlorosis in apples. I offer this only as an aside that may or may not provide insights. I had an issue with Iron chlorosis when I first started growing chestnuts indoors under lights. Adding Ironite had no positive effect. Eventually I figured out the problem. It was not that the mix was low in iron, it was the iron was not available to the chestnuts because of the pH. The mix I was using was adjusted to neutral and so was the tap water. I was finally able to salvage those trees by adjusting the pH to make it more acidic. I used some acidifier for blueberries and switched to rain water. I've collected and used rain water ever since. That alone adjusts the pH enough that I have not had an Iron chlorosis issue since.
I don't know enough about apples or clonal rootstocks to know if there is any correlation here, but at least some trees can be limited in the amount of iron they can uptake if the soil is insufficiently acidic.
Thanks,
Jack