Teresa, we are zone 7 NW GA. I am still planting and will be for a couple more weeks. The Weather Channel is showing 27 as our low for Saturday morning. Last year I planted fall through winter with no problems. Everything came through the winter just fine, and it was one of coldest on record for us. I put alfalfa pellets and Milorganite in the planting holes which probably helps to warm the soil for the roots plus I mulch. I agree that the ground is warmer than in pots. I would go ahead and plant.
Doris