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 theirway 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 therefar 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
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 isnota 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 environmentinNow is the Season to Take Houseplant Cuttings.
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!
As a seasoned horticulturist with years of practical experience and a deep understanding of plant propagation techniques, I'd like to shed light on the shortcomings of rooting cuttings in water, drawing from a wealth of knowledge gained through extensive experimentation and hands-on gardening.
The practice of rooting cuttings in water has been a tradition among gardeners for generations. However, while it may yield success in certain cases, it is not the most optimal method for various reasons, each backed by tangible evidence.
Firstly, water-rooted cuttings tend to suffer from an excess of moisture without a proportional supply of oxygen. Plants require both water and oxygen to root effectively, and stagnant water on a windowsill gradually becomes oxygen-depleted. This suboptimal environment not only hinders root development but also promotes the growth of harmful bacteria on the stems, forming a sludgy coating that can lead to rot. Furthermore, the natural rooting hormones released by the stems are diluted in water, diminishing their effectiveness.
Fast-rooting plants like coleus and begonias may fare reasonably well in water, but other cuttings, especially those with longer rooting times, often experience a decline in health due to the deteriorating conditions of their water environment.
Moreover, even when successful root development occurs in water, leaving the cuttings submerged for too long poses challenges during transplantation. The roots become entangled, making it difficult to transfer the plant intact. Fine roots, in particular, clump together and are prone to breakage when removed from the water, resulting in a compromised root system.
The recommended alternative is to root cuttings in a well-aerated and relatively sterile substrate. Materials such as potting mix, seedling mix, vermiculite, coarse sand, and perlite are suitable choices. Avoiding garden soil, laden with microbes, is crucial to maintaining a healthy rooting environment.
For woody cuttings, applying rooting hormone before placing them in the substrate is beneficial. On the other hand, green cuttings can be directly inserted into a moistened substrate without the need for additional hormone application.
In conclusion, if you find it hard to break the habit of rooting cuttings in water, it is essential to transition them to potting soil promptly once signs of root development, indicated by small white or yellow nubs on the stem, become apparent. Delaying this transfer could lead to adverse consequences, emphasizing the importance of ensuring a smooth transition to a terrestrial environment within 3 or 4 days.
