Do you have a lot of transparent PET bottles? More than can be used as water bottles on your kids’ camps? You can of course put them into the recycling bin but here’s a way of giving them one more chance to be useful before they get recycled.
I have just learned that these seedling protectors are called cloches which is a French word meaning “bell”. With that in mind, you will be able to imagine how to make these homemade cloches. Very easy. Just cut off the bases and place them over your seedlings! If there’s no risk of overheating (like in the middle of winter without freak weather), you can place the lid on to keep the plant warm. Otherwise, it’s important to have ventilation when the sun comes out. Either remove the lid or just the cloche.
Apart from keeping the plants warm when you need to, they also shelter them from harsh weather like hailstorms and protect from pests. I used the cloches mainly for the latter!
When the weather warms up and the cloches are no longer needed until the next season (unless you have many pests like I do, grrr!), you can store them by threading them onto a bamboo stick. If any are worn out, then just recycle them.