It may not feel like it yet, but spring is just around the corner and it is time to think about repotting. For many new to the hobby of orchid growing, the thought of repotting can be terrifying. For those of us that have been growing for awhile, it is a lot of work, made much easier if all the supplies needed are ready when the orchids are.
Many new growers are anxious to repot so they can divide their orchids.
The real question should be, “Does this plant need to be divided?”. If
the medium is degraded the orchid should be divided. Orchids that have 3
or more bulbs out of the pot are likely candidates too. However, if
grown in some type of inorganic medium, e.g. Aliflor, one can simply cut
the 3 bulbs that are out of the pot off and leave the remainder in the
pot.
Determining if the medium is degraded or not can be tricky, even for
experts. This was discussed in January’s column. If growing in some type
of bark, shove a finger into the medium. If it is easy to push through
the medium or if the medium feels mushy, then it is time to repot. If
some of the bark feels hard, but there are mushy spots jet some water
through the pot or hold the pot upside down and then jet water into the
pot. If the orchid falls out it is ready to repot. If not, you can get
another year in this pot by adding a handful of new bark as a top
dressing.
Paphs and phals usually need to be repotted each year unless grown in
large bark or rock. Typically, most phals are purchased in a soilless
mixture or sphagnum, both of which seldom last more than a year. Paphs
are especially prone to root death unless repotted frequently or top
dressed with dolomite lime.
Treat intergeneric oncidiums and dendrobiums as you would cattleyas with
respect to both timing and frequency of repotting. Dendrobiums prefer to
be in pots into which they just barely fit, making large plants prone to
tipping over. Just place the small pot into which your newly repotted
dendrobium was just potted, into a larger clay pots to prevent tipping.
Never over- pot a dendrobium, no matter how large the plant.
Early spring is usually the best time to divide because most orchids are
going into a growth mode and will be able to replace roots damaged
during repotting. Most orchid hybrids and species have or are about to
initiate new growths, so care needs to be exercised so that these
fragile green nubs are not damaged. There are some exceptions to this
rule, notably with species. Some bifoliate (two leaves per bulb)
cattleyas should only be repotted when getting new roots even with the
risk of damaging the new root tips. Repotting before or after this time
will severely set the plant back or even result in its death.
Repotting assumes that you have everything you need, which should be
done now if you have not already done so. Do not wait until the last
minute to purchase what you need since supplies can often be hard to
find once all of the growers in the U.S. begin repotting. Always
overestimate what you will need. If stored properly, unused supplies
will last for years.
Be sure to keep track of each plant’s name. That is critical, not just
for exhibiting, but also so that you can check the growing requirements
if needed.