I've had my garden going for at least a few weeks. I just cover the plants I'm worried about when it gets below freezing. I've been saving milk jugs and cutting the bottoms off, then putting them over the more tender plants out there. You can take the lid off to vent, and they work nice. Like a mini greenhouse.
That is such a fantastic idea! My kids drink milk like it's going out of style. I'm going to start saving all those jugs!