I live about a mile high, where there is lots of snow and sub zero temps in winter. I grow a surprising amount of basil, parsley and thyme on the small shelf between my kitchen faucet and an old double pane, but essentially uninsulated, window. Two inexpensive self watering rectangular planters were giving me a little trouble with plant damage in winter, until I placed a row of plastic "pillows" salvaged from pkg. shipments between the planters and the window. That seems to keep the soil warm enough I can grow year 'round without difficulty. This is a south facing window, so sunlight is adequate year 'round.
Wow! I have a lot of those...though I have a NW facing window by my kitchen's planters. But upstairs in our bedroom we have the same planters and it got a lot of sunshine because it is located at the west side of the house...I will remember this today so i can get some packaging materials down the basement for this. Thanks a lot for your tip.
Bill and Izzie: Proud parents of a soldier. Looking back on all the mistakes I've made in my life, all I can say is I've gotten a lot of miles out of stupid.