While the traditional Mother’s Day planting date has come and gone, we are still having some cool nights. While the cool evenings won’t harm most of your plants, they can slow down growth, especially on tender young seedlings. Using a cold frame or bell jar is a tried-and-true method to speed up your garden’s growth! Here’s some simple (and cheap!) DIY cold frames I found around the web that you can use to protect your plants on cold nights.