Cactus and succulents Gardening Houseplants Plant propagation

When to Use a Mini-Greenhouse for Cuttings

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All sorts of transparent containers can be converted into mini-greenhouses for cuttings.

Taking cuttings of houseplants is simple enough – in most cases, you just stick the cutting upright in moist potting mix and you’re off to the races! – but you’ll have more success by covering the still-fragile future plant with a mini-greenhouse of some sort. After all, cuttings don’t yet have roots and can dry out very quickly when exposed to the air, losing water to evapotranspiration. This is doubly true for cuttings with thin leaves. If you cover them with a mini-greenhouse, though, the air inside will be saturated with moisture, and therefore the cutting will no longer lose its precious water to transpiration, giving it a better chance of recovery.

You can use just about any transparent container as a mini-greenhouse: a transparent plastic bag (prop it up with coffee sticks so the bag doesn’t collapse on the plant), a wide-mouth bottle turned upside down, a clear plastic container for vegetables, fruits or pastries that you recycled, or even the bottom of a soft-drink bottle you’ve cut specially for this purpose.

Remove the greenhouse when new leaves start to appear, indicating that rooting has begun, which may take a few weeks. Your cutting is now an officially rooted plant, ready to grow on its own and greenhouse care is no longer needed.

Some Cuttings Like It Dry

If the vast majority of cuttings benefit from high atmospheric humidity while they are rooting and should therefore be placed in moist soil and covered with a mini-greenhouse, there are some cuttings that root best under drier conditions. And this is especially the case with succulents, a group that includes desert cacti, crassulas, sedums, aeoniums, and many others.

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Wait until succulent cuttings callus over before potting them up. This cactus cutting, for example, might take a month to callus over.

For these plants, cut off the top of the stem, but don’t plant it right away. Let it dry for a while, until the wound callouses over, before potting it up. You can simply lay the cuttings on their side on a plate or a shelf while you’re waiting. It takes 2 to 3 days for most succulents to form a callus, but a month or more for those with very thick stems (large cactus and euphorbias, especially).

Stick the cutting upright in a pot of dry soil (not moist as you would for other plants) and don’t water right away. Wait until you see signs of growth, which can sometimes take a month. Yes, as odd as it may seem, these plants will more easily produce roots in dry soil! And of course, don’t cover them with a mini greenhouse, as this could lead to rot!

Once new growth appears, start a normal watering program and your “succulent cutting” will soon be a thriving plant!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

3 comments on “When to Use a Mini-Greenhouse for Cuttings

  1. Reblogged this on Sustainable Food for the Globe and commented:
    You have to visit the Laidback Gardener blog just to see Larry Hodgson’s picture. The first time I saw it I laughed so much my stomach hurt. He is always a great read.

  2. Pingback: Frosted Fern: A Christmas Mystery Plant – Laidback Gardener

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