By: Maggie McCarthy
Important to remember:
Many plants will easily root in water. However, the roots that form can be extremely fibrous and stringy. Plants rooted in water often have a difficult time becoming established after they are transplanted to a container.
The propagation medium should be thoroughly moistened before use. Many organic materials, like peat moss, have a waxy outer coating that resists wetting. Be sure to apply water slowly to obtain uniform distribution. This may require 2-3 applications. It is not uncommon for a medium to look wet on the surface but to be powdery dry in the middle. A well moistened media will make it easier to stick cuttings later on.
Light is an important environmental factor in plant propagation. Generally speaking, low light levels cause plants to root slowly. However, high light intensities can stress cuttings, causing them to burn or drop leaves. Diffused sunlight generally provides enough light for optimum rooting without causing injury to the cuttings.
Since cuttings do not have roots, they cannot replace the water lost through transpiration. Therefore it is important to maintain high humidity around the cuttings to cut down on the amount of moisture lost to the atmosphere.
These conditions can be provided by placing a clear piece of plastic over the propagation area. This causes condensation to form on the underside of the plastic that provides the necessary humidity.
Ventilation is also required to avoid disease problems. The plastic covering should be placed such that air can flow freely around the cuttings as they root.
For best results, maintain day temperatures at 70 degrees F. During winter months, soil can be as much as 10-20 degrees less than air temperature, so provide bottom heat when possible. Ideal rootzone temperatures for most plants are approximately 70-75 degrees F.
Rooting hormones are often used to promote root formation, a naturally occurring plant hormone that is responsible for root development. The basal end of the cutting is dipped into the chemical prior to sticking it into the propagation medium. These products come in different strengths and will vary according to the type of plant being propagated.
Stem and Section Cuttings:
There are two types of stem cuttings: tip cuttings, which include the apex or plant tip and a small portion of the stem; and section cuttings, which include a 2- to 3-inch section of stem, and leaf joint.