I try to re-use many things around the house for our garden. I have found that milk jugs are good for milk but also good for my tomato plants and pepper plants.
Here is how I use that old milk jug:
I cut about 2 inches off the bottom of a milk jug. I then place the jug over my new little tomato plant or pepper plant... *when I hear the weather is going to get cold* I keep the lid off the jug for ventilation. ***This should keep my plants safe from a frost***
I also use milk jugs to keep my plants warm in our cold frame...just fill up milk jugs with warm water and set near plants in cold frame the heat should keep your plants warm over night. ( I spray paint my milk jugs black this keeps the jugs water warmer.) (solar heat)