In spring, when trays of seedlings and cuttings start to fill our homes, transparent mini-greenhouses are ideal for covering the soon-to-be plants. They help create the famous “greenhouse effect” young plants so love, keeping both seedlings and cuttings in warmth and high humidity … just what they need for a good start in life. You can, of course, buy plastic domes specifically designed for this purpose: every garden center sells them, as do seed catalogs, but you may already have everything you need at home … in the form of plastic bottles: water bottles, juice bottles, soft drink bottles, etc.
If you cut a plastic bottle in half widthwise, you will get not one, but two mini-greenhouses: the base, inverted, and the top. (Yes, do leave the cap on: you’re striving for high humidity, after all!)
Small bottles, like individual portion water bottles, are fine for small pots. 2-liter bottles will cover larger ones. And you can find even larger bottles if you look a bit.
Note that these mini-greenhouses are only used for a short time, just to get seeds and cuttings stared. Once seedlings germinate and cuttings are rooted, you don’t need them anymore, as young plants have to adapt to real-life conditions, including less humid air. So the fact that these home-made coverings are not that tall is not a problem: you’ll have removed them long before the young plants reach their top.
Making the Cut
To cut a plastic bottle in two, use a sharp knife or utility knife (X-Acto) to pierce the initial hole. You can continue cutting all around the bottle with the same knife if you want, many people prefer finishing with scissors. They’re a little less hazardous for your fingers! Just experiment to find out what works best for you.
After use, clean your mini-greenhouses by wiping off any soil that sticks to them and stack them for use the following year.
Best of luck with all your seedlings and cuttings!