Most people who
grow cactus plants eventually want to increase their collection
through propagation. In most cases, propagation of cactus
is quite easy. Seeds, cuttings or division can all be used
to propagate these plants, with the best method depending
on the type of plant.
seed is an inexpensive but slow way to introduce unusual and
exotic cacti to your collection. Nurseries, mail- order houses
and specialized cactus societies usually have cactus seeds
available at a relatively low cost. Seed may also be collected
from any cactus plant that has flowered either in your home,
or in nature, by simply removing the ripe pods. Fully mature
pods should be cut open, and the seeds squashed out onto a
piece of paper towel where they can dry at normal room temperature.
Rapid drying of the seeds will reduce the chances of rot occurring.
If you plan to store the seeds for any length of time, they
must be fully air-dried before being placed in storage.
Early spring is
the best time to sow cactus seed. This is because seedlings
that germinate in springtime have the benefit of summertime
light levels in which to establish themselves. A small pot
(5 cm) or shallow pan is ideal for germinating the seeds.
Whatever container is used, it should be filled nearly to
the top with rich, free-draining cactus soil. After firming
the growing medium, seeds can be evenly spread on top. The
seeds can then be covered by sifting a very thin layer of
sand over top of them. The layer of sand should be very thin,
and should permit at least a small amount of light to reach
the seeds. The newly sown seeds can then be watered by sitting
the pot in a shallow tray of water until the top of the growing
medium has become moist. You may wish to add a fungicide such
as No-Damp to the water to help reduce the incidence of damping-off.
After the pot has been permitted to drain completely, it can
be covered with a clear plastic bag, and placed in a location
that receives bright light, but where there is no direct sunlight.
Direct sunlight will result in a rapid heat build-up in the
bag, and could easily kill the delicate seedlings.
Depending on the
species, seedlings can be expected to emerge over a period
of 2 to 16 weeks. If a mixture of seeds was planted in the
same pot, it is best to wait until no new seedlings are seen
emerging before disturbing the young plants. Once several
weeks have passed with no new seedlings emerging, the plastic
bag can be removed, and a bit more sand sifted over the seedlings
to provide them with better support and reduce the chances
of damping-off. The seedlings should not be introduced to
full sun for at least one year.
as the seedlings are not crowding each other, it is probably
best to leave the young plants in the original pot. Plants
should be placed in individual pots only once they have begun
to crowd one another. Newly potted seedlings should be kept
in a cool location with bright light for several weeks. After
this time, they can be slowly introduced to brighter and brighter
light, until they are growing in a location with full sunlight.
of cacti through cuttings provides larger plants much more
quickly than propagation from seed, but far fewer plant can
be obtained. Those types of cacti that are columnar, pad-forming
or those with segmented stems such as a Christmas cactus are
easily started from cuttings. As with seed, spring is the
best time to take cuttings, as most cacti will be emerging
from their winter rest at this time and initiating new growth.
The size of the actual cutting taken can be quite variable.
On a Christmas cactus, a couple of stem segments may be used,
with a total length of a few centimetres, while on some columnar
cactus plants, a single cutting may be as long as a meter.
An important point is that the plant that you are taking the
cutting from should be in as healthy a condition as possible.
When taking a cutting from a stem section, use a clean sharp
knife. If you are taking several sections from one long stem,
you must remember which was the top and the bottom of each
piece, because a stem piece that is planted upside down will
not grow. A simple way of keeping track of the top and bottom
is to cut the bottom of each segment on a slight angle, and
the top straight across. For pad-forming, or branching cacti,
the cuttings should be taken at the joints so that the mother
plant is not significantly disfigured. A single oval pad from
a pad-forming cactus makes an ideal sized cutting.
The primary problem
encountered with cactus cuttings is the development of fungal
soft rot. This condition begins at the cut surface and eventually
reduces the entire cutting to a slimy mass. Two techniques
are recommended for avoiding this problem. The first is to
simply allow all fresh cuttings to sit in a warm dry place
for from 1 to 14 days before they are placed in the rooting
medium; the larger the cut surface, the longer they should
be allowed to dry. During this time, the cut moist surface
will form a dry callus which is far less prone to rot. Although
it sounds slightly alarming to leave a newly taken cutting
sitting exposed for several days, remember that a cactus is
able to survive periods of drought. As long as the cutting
is not noticeably shrivelled, it is probably alright to leave
it dry. Newly cut stem segments may also be dipped in garden
sulphur before planting to prevent the onset of soft rot.
will root in a standard well-drained cactus mixture if provided
with bright light and cool temperatures for several months.
Although the cuttings may not have a developed a root system,
resist the temptation to keep their soil any wetter than you
would a normal cactus plant. The wetter the soil, the more
likely the cuttings will rot.
is an ideal method of propagating those types of cactus which
bud off new plants from the side of the mother plant. These
offsets usually already have roots developed and need only
be carefully pulled or teased away from the parent plant and
placed in a pot of their own. The advantage of this type of
propagation over the taking of cuttings is that division leaves
the mother plant with almost no signs of disfigurement. Where
cuttings are taken from non-branching types of cactus, the
mother plant is often left in an unattractive condition.