Will be planting 40+ grafted apple trees this Spring. I have seen some videos mentioning putting a small amount of wood ashes at the bottom of the whole when you plant the tree. Anyone with experience, is it a good idea/ does it seem to help?
Also, anyone with experience on root growth stimulants (seaweed, kelp, etc.)?
Not meaning to sound funny but I really am looking for experience or science not opinions (everyone has at least one!).
A small amt. of wood ashes in the planting “hole” (not whole) wouldn’t hurt. Too much could be damaging…as it’s alkaline.
I know someone who dumped wood ashes on his blueberries and killed all of them. 
(Nope, wasn’t me.)
Wood ash is supposed to promote flowering. I tried mixing when planting and sprinkling on top of others. I do not think it has any benefit. Not visible benefit anyway.
Wood ash is basically a fast acting 1-2-3 fertilizer that also has a fast liming (ph raising)effect, a little goes a long ways
Extension services of UNH states this: Wood Ash as a Liming Agent - Acidic soils (below a pH of 6.0) reduce the availability of most plant nutrients and can reduce biological activity in the soil. “ Wood ash contains significant amounts of potassium and calcium, while providing smaller amounts of phosphorous and magnesium.”
So a scientific approach would be to have a soil test done to determine if your soil needs a pH adjustment or is deficient in potassium, calcium, phosphorus and/or magnesium. Too much of any nutrient/micro nutrient can adversely effect uptake of other nutrients.