I think that this subject may have been touched on in the past but, with the arrival of the fall season, idle minds turn to concerns about the future…
I know that we don’t fertilize with the usual N,P,K formulas in the fall.
But, do we have anything to support the concept of a fall feeding of micro-nutrients (ex. azomite etc.) will held improve the flavor profile of fruit in the following season.
The roots are still active long after the leaves have fallen. They must be doing something to prepare for the next year. Micro-nutrient minerals might take longer to be uptaken ( is that a word?) so a fall feeding may give the time needed for the tree to integrate the stuff.
My opinion is to wait until spring. As much as i would like to say something different its my belief all fertilizers and minerals should be applied during the growing season so that more can be absorbed into the plant. As an example Bitterpit is a problem in apples controlled by applying calcium in the spring and other unrelated methods http://treefruit.wsu.edu/article/calcium-recommendations-for-apples/
I see your point and I was not looking to make more work for myself this fall.
The thought that came to me was that, just like with sulfur where it takes the our microscopic Santa’s Helpers some time to act on the the stuff in the soil, the same might apply to some of those minerals that might need to be somehow converted by the micro-fauna in the soil in order to make it available to the trees. I was looking to see if I needed to get a jump start on the process.
Probably would not make a material difference, but, I was just wondering.
Rock powders are best applied in the fall to allow time for digestion. Soft rock phosphate, for example when added in the fall with a little lime will hold in the soil profile and provide benefits for years to come. (Assuming soil calcium levels are not too high.) As it is not a salt based fertilizer it takes time before the plant can use it.
Most micronutrients do require fungi and bacteria to uptake. Personally i wait to fall fertilize until leaf drop is finished. My understanding of what roots do during winter is root growth and nutrient back up storage, Plants don’t store a ton of nitrogen so if you medium strength N feed them that is like a really early Nitrogen application in the spring (Not good for me) However potassium phosphorous and micronutrients I do think will have a beneficial effect if applied naturally (Something the soil life will use). Also Im less busy in the winter and spring i never can get enough done so i enjoy it and do like to use rock dusts like azomite. I also do alot of spring and summer clean up in the warmer winter days.