Successful wintering is dependent upon the last rounds of bees emerging in the late summer/fall having adequate pollen available in the broodnest.
It may be time for the beekeeping industry to shift its paradigm from managing boxes to really thinking about good husbandry of the critters inside. Think of each box as having a living animal inside. Don’t be afraid to invest in their nutrition, either by moving them to better pasture, or by feeding them in place.
Michael Cox wrote: are those pollen trap hives used to collect pollen for sale, or to supplement other colonies pollen stores?
We have always had good success collecting in the summer. We do not collect in late summer/fall. During humid months, you really should be collecting every day. A good hive for us produces approx. 1.5 lbs a day.
Another tip, do not be tempted to try and turn the trap "off and on" frequently thinking you will make it easier on the bees. This can stress the bees out. The bees sometimes need a week to get acclimated. Once they are collecting, keep it going for 2-4 weeks during a good pollen flow. You really don't have to worry about the bees not having enough pollen. Not all pollen is stripped, and once the hive detects that there is not enough pollen coming in, workers switch to pollen gathering from nectar to maintain the correct balance.
Michael Cox wrote:
On that basis I find the idea of individuals planting "a lavender bush for the bees" rather laughable.