Re: What is the purpose of fall feeding?
I do fall feeding, but only because where I'm at, there's not a fall nectar flow. I feed in mid August thru mid October with sugar water syrup and pollen patties. I stop by mid October for them to get time to cure the nectar and seal up the hive and combs the way they want. I give the pollen patties to help stimulate a bit of brood rearing to get some young bees onboard to last the hive through until early spring.
I hate having to feed bees, as honey stores are much better for them than sugar water syrup stores, I think. But with lack of flow in late summer and early fall, I feel I would not bee a responsible beeker if I let the hives reduce in numbers because of lack of flow in the fall, to the point that it would be questionable if they would make it through the winter or not.
20+ years, raise my own queens, feed when needed. I treat, but have not perfected varroa management yet.