Propagation Media:
A good propagation medium is made up of components that provide optimum
aeration, drainage and moisture holding characteristics. These are usually
made up from combinations of peat moss, perlite, vermiculite, sand or
similar materials. The primary role of a propagation medium is to provide
support and moisture while the plant is developing. These requirements are
quite different from those of a potting medium, which may have to sustain a
mature or growing plant over a long period of time. Generally speaking,
potting media are not recommended for plant propagation purposes.
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.
Moisture:
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:
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.
Humidity:
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.
Adequate 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.
Temperature:
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 root zone temperatures for most
plants are approximately 70-75 degrees F.
Rooting Hormones:
Rooting hormones are often used to promote root formation. These materials
provide supplemental auxin, 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 (not including the apex or plant tip>
and leaf joint.