Yesterday was supposed to be our last frost date. I know it sounds early, but Boston stays quite a bit warmer than the surrounding area thanks to the water and the winds and all. During the winter it's usually several degrees warmer and we get a few inches less snow than people even 30-45 minutes away.
Our Spring has been unusually cold though, so I wasn't holding my breath that the frost warnings were actually done. Good thing I didn't. Look at the email I got last night.
The upside to container gardening is that instead of finding coverings for all of my in-ground crops, all I had to do was move the peas and lettuce inside and close up the mini greenhouse. The greenhouse company states that the inside temperature will drop to the outside temperature at night without an additional heat source. When I went out this morning, there was some condensation on the inside and it felt quite a bit warmer than the outside temperature. This means one of two things: 1) My little greenhouse is really well set up and isn't allowing much air in without the door open. 2) My house is so old and so poorly maintained and insulated that our heat leaked out and kept the greenhouse warm. My bets are on option 2. :(