Starting Cuttings in Water: Not Such a Good Idea

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The roots of these coleus cuttings are far too long: pot them up without delay.

For generations, gardeners have been rooting cuttings in a glass of water placed on the 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.) 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.

Secondly, even when the cuttings root successfully in water, people tend to leave them there far too long a time. 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 can possibly lead to rot: not such an auspicious beginning!

Rooting Cuttings in a Substrate

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Root cuttings directly into a substrate.

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, but just slip green 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.

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Transfer cuttings from water to a terrestrial environment as soon as you see the first signs of roots.

Still Sticking With Water?

Old habits die hard and if you wish to continue rooting cuttings in water, that’s your business. 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!

8 thoughts on “Starting Cuttings in Water: Not Such a Good Idea

  1. Anton

    Yes I think I just wanted to say hubiscus newly calloused in water can be kept for a week or two no problem. I collect hibiscus cuttings on my travels and keep them leaves (halved) and all in inflated zip lock bags with about a cm of water inside. They callous very quickly with good ambient heat (bag in the shade), yes in a matter of days. I soak the cuttings in water for three to four hours first, the entire thing completely submerged, with a systemic antifungal solution. This makes the cuttings leaves turgid, how they basicaly stay once in the bags and prevents rot. Once they have calloused in the bags I pour out most of the water and seal again, you just need enough moisture in there to keep the bag misted at all times, a spray or two ammount will do it. When I get home, sometimes a bit over two weeks later I plant in soil and they are away. Calloused cutting have the advantage over non calloused cuttings in that they can immiediately start taking up nutrients and water, no set back, they also don’t need to be quite so damp when planted. Where as uncalloused cuttings often rot in substrate as they take a long time to callous and need lots of moisture and humidity. So if you can get them calloused as quickly as possible so much the better. Soaking then keeping them in more or less 100% humidity does this quite effortlessly. I would always include the fungicide as this guarantees they wont turn to mush at any stage. The newly cut cuttings absorb the systemic fungicide into the tissue so they don’t rot once planted either. This is the quickest way I know how to root cuttings. It takes approximately two weeks in the begining of the wet season and is especialy good for difficult to root cultivars. if the cuttings are plentifull just sticking hardwood cuttings (leaves trimmed) into the ground during the wet season also works a treat. A good percentage will root and grow, one or two may not make it so stick them into the ground quite closely, you can space them later by pulling up ones that made it but are too close.

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