Plant propagation

Cuttings in Water: Maybe Not the Best Idea

Begonia cutting rooting in water

The roots of this Begonia ‘Cracklin Rosie’ are far too long: pot it up without delay! Photo: Behnam Mancini, Wikimedia Commons

For generations, gardeners have been rooting cuttings in glasses of water placed on a windowsill. And it works … sometimes. But it’s still not the best way to root cuttings.

You see, cuttings grown in water get too much of a good thing: H20. Yes, they need moisture to root, but they also need oxygen. And as water sits on a windowsill, it becomes more and more stagnant (oxygen-depleted). Also, most stem cuttings give off their own rooting hormone … that is diluted and therefore less effective when they sit in water. Plus, harmful bacteria start to form on stems sitting in water, coating the stem and new roots in a gooey sludge, while rot-causing fungi, which do best in an oxygen-depleted environment, tend to move in and work their way into the stem. Fast-rooting plants (coleus, begonias, etc.) usually do all right in water, but other cuttings seem to start well, then go downhill. As well they might, given the declining state of their environment.

This poor cutting has spent far too long in water. Its abundant roots may well not survive the transition to soil. Photo: Biusch, Wikimedia Commons

Secondly, even when the cuttings root successfully in water, people tend to leave them there for far too long. Soon the glass is full of roots that are impossible to transplant intact, especially fine roots, which clump together when you take them out of the water and tend to break when you spread them out as you pot them up. Your newly rooted plant can lose half its roots or more as you plant it and each wounded root that does survive has an open wound that can possibly lead to rot: not such an auspicious beginning!

Rooting Cuttings in Substrate

You’ll have far better results with most cuttings if you root them in soil or some other substrate. Photo: Claire Tourigny

You’d do better to root your cuttings in a tray or pot of some sort of substrate: it just needs to be well aerated and fairly sterile. Potting mix, seedling mix, vermiculite, coarse sand and perlite are good choices. (Pelargoniums especially seem to prefer sand or perlite.) 

Soil fresh from the garden is not a good choice, contaminated as it is with microbes! 

You can apply rooting hormone to woody cuttings to stimulate better rooting, but just slip soft-stemmed ones right into a moistened substrate. 

You’ll find more information on rooting cuttings in a terrestrial environment in Now is the Season to Take Houseplant Cuttings.

Still Insisting on Rooting in Water?

Transfer cuttings from water to a terrestrial environment as soon as you see the first signs of roots. Photo: Gmihail, Wikimedia Commons

Old habits die hard and if you wish to continue rooting cuttings in water, that’s your choice. Just don’t wait too long before potting them up. As soon as you see small white or yellow nubs appear on the stem (these are future roots), transfer them to potting soil so they can start their life in an appropriate terrestrial environment. In some cases, that means your “cuttings in water” will need to be potted up in just 3 or 4 days! 

Article adapted from one published in this blog on March 14, 2016.

Larry Hodgson is one of Canada’s best-known garden communicators. After studies at the University of Toronto and Laval University where he obtained his B.A. in modern languages in 1978, he succeeded in combining his language skills with his passion for gardening in a novel career as a garden writer and lecturer. 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 is a regular contributor to and horticultural consultant for Fleurs, Plantes, Jardins garden magazine and has written for many other garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening, Rebecca’s Garden 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 50 other titles in English and French. He can be seen in Quebec on French-language television and was notably a regular collaborator for 7 years on the TV shows Fleurs et Jardins and Salut Bonjour Weekend. He is the President of the Garden Writers Association Foundation and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. An avid proponent of garden tourism, he has lead garden tours throughout Canada and to the gardens of over 30 countries over the last 30 years. He presently resides in Quebec City, Quebec.

1 comment on “Cuttings in Water: Maybe Not the Best Idea

  1. Exactly!
    This is common with pothos, and people actually grow them as houseplants in bottles of water, and just replace the water regularly. When they get around to planting them, they believe that it is best to plant the who big mess of roots. I try to explain that the roots need to be pruned, but no one believes me.

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