Plant propagation is the process of creating new plants from a parent plant. Water propagation is a popular, straightforward method where a cutting is placed directly into water to encourage root development. Gardeners often consider using rooting hormones to speed up this process. Rooting hormones contain plant growth regulators called auxins, which stimulate cell division and differentiation at the cut site, promoting new root formation. The question is whether these commercial rooting aids are beneficial when using the water-based technique.
The Role of Rooting Hormone in Water
Commercial rooting hormone, typically sold as a powder or thick gel, is generally not recommended for water propagation. These formulations are designed to adhere directly to the cutting before it is placed into a solid medium. When a cutting coated in dry hormone powder is submerged in water, the active ingredients are quickly washed away. This renders the hormone ineffective because the auxin concentration cannot be maintained at the necessary level for consistent results.
The inactive carrier agents used in commercial powders can introduce foreign materials into the water. This residue clouds the water and creates a less-than-ideal environment for the cutting. These dissolved materials may encourage the proliferation of bacteria and fungi. This can lead to stem rot and the failure of the cutting. Therefore, common powder or thick gel hormones should be avoided for water propagation.
Successful Water Propagation Without Hormone
Successful water propagation relies on proper technique and maintaining a clean environment, not synthetic hormones. The first step involves taking a clean cut just below a node. The node is the area on the stem where natural auxins are concentrated and new roots will emerge. Ensure that at least one node is fully submerged in the water. Remove any leaves that would sit below the waterline to prevent them from rotting.
The environment should be warm and bright, but avoid direct sunlight which can overheat the water. A consistent temperature, ideally between 68 and 75 degrees Fahrenheit, encourages metabolic activity and root initiation. Oxygen availability is a crucial factor in water propagation, as roots require oxygen for growth.
To maintain a high level of dissolved oxygen and prevent anaerobic bacteria buildup, the water should be changed completely every two to three days. Using a glass container allows easy monitoring of water clarity and root development. Some gardeners find success by adding a cutting from a plant that naturally releases rooting compounds. Examples include a willow branch or a piece of golden pothos, which naturally boost the water’s rooting potential.
When Rooting Hormone Is Necessary
Rooting hormones are most effective when propagating into a solid, sterile rooting medium, such as perlite, coco coir, or potting soil. Their primary purpose is to provide a concentrated dose of synthetic auxins directly to the wound site. These auxins include Indole-3-Butyric Acid (IBA) or Naphthalene Acetic Acid (NAA). This localized application increases the percentage of cuttings that successfully root. It can also significantly reduce the time required for new roots to form.
These commercial products are useful when propagating semi-hardwood or hardwood cuttings, which are more difficult to root than soft, herbaceous cuttings. The hormone is applied by dipping the base of the cutting into the powder or liquid. The cutting is then immediately inserted into the prepared medium. This ensures the auxin is absorbed at the cut surface to stimulate root cells. For easy-to-root plants used in water propagation, commercial rooting hormone is unnecessary.