These plants won't be around at that time. I usually get about 2 months of harvest out of them before the plants get tired and start to bolt. So I have a consistent cycle of starting new plants every couple weeks. Even though I do have row covers on 3 beds and sort of on a fourth (needs to be completed) and have some bok choy, and other frost hardy greens growing under them. The kale would most likely be fine without a row cover but the plats under the row covers are outgrowing the ones that aren't.
I actually stopped harvesting a few weeks ago the inside plants that is. I just was getting tired of salads all the time. Need to look up a few new types to make.