Zinc!
September 01, 2021 09:58PM
I just got the results of a late (8/27) leaf analysis I did and it indicated that zinc levels were low or deficient. The pH of the soil is not high (it's a bit low) and neither are phosphorous levels. Zinc is the only mineral in our soils that test above the optimum--so it seems strange that it is deficient in the leaves. We've had a lot of rain this summer. Probably too much for our heavy soils. Could that be the culprit? Or maybe zinc is one of the first things to go as trees head toward fall?

Nat Bouman
Growing cider varieties in Zone 5b
On B.118 at 18X24
Susquehanna County, Pennsylvania
Re: Zinc!
September 02, 2021 04:02PM
Soil results for Zn are generally accurate whereas plant sap offers the most revealing analysis of all. Mineral ash via leaf tissue gives an indication of what's going on, however, I wouldn't take those results as gospel for this particular nutrient. Zinc should be supplemented if short of the mark but never pushed into excess as there will be repercussions on the manganese front.

Anyhow, I applied zinc sulfate this spring in my East block (based on marginal soil results) at a rate of 4 ounces per tree across a 6-8 foot radius. This amendment dissolves readily so a spray application to the ground is another means of getting this done. Sounds like this is not what you need, Nate, based on prior soil results.

Prime timing for a zinc foliar is when making a 'Spur Potential Spray' some 4 to 6 weeks before the trees actually go dormant. This in conjunction with calcium, manganese, and boron. Having sap results from around the time of terminal bud set is the basis by which I make the decision to include foliar zinc or not in this application. (I will be including a pint of Rebound-Zn in the north and east blocks but zinc levels look good in my south block so none in that tank mix.) There's a direct correlation between adequate Zn and good leaf size which is a more intuitive way of judging how things stand.

.

Lost Nation Orchard
Zone 4b in New Hampshire



Edited 1 time(s). Last edit at 09/02/2021 04:07PM by Michael Phillips.
Re: Zinc!
September 03, 2021 05:35AM
These are really valuable insights as to how to confront a zinc deficiency but I'm just baffled as to how my soil tests show an abundant level of zinc--almost too much--and yet the leaves indicate that they are struggling with not getting enough zinc. They lack this mineral more than any other nutrient/mineral.

Nat Bouman
Growing cider varieties in Zone 5b
On B.118 at 18X24
Susquehanna County, Pennsylvania
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