I made a few adjustments to this great cold frame/greenhouse DIY: 1) flip the box upside down and use it as a cloche to cover the plants so the clear part is on top. 2) use the lid as the base & line it w/ black plastic/paper to absorb more heat from the sun. 3) use biodegradable 4oz espresso cups (google to buy) for seeds. To transplant seedlings, cut bottom off cup, place in the ground - updates & new projects at the 2 DIY Board, https://www.pinterest.com/mclovebuddy/2-diy-garden-outdoors/
2-liter Soda Bottles have several great uses! If you cut the bottom off, you can use them to cover seedlings like mini greenhouses (or cloches). They also protect them from frost, wind, and strong rain.