How do I get my orchid to grow roots? This is one of the most asked
questions because so many new orchid growers start with the gift of a
pot plant that, unfortunately, stays too long in the medium. But even
those of us who have grown orchids for many years can find individual
clones or times when an orchid just will not grow roots.
When the weather is warm most orchids will readily grow roots. There may
be a few exceptions to the rule, but even those will at least grow a few
new roots this time of year.
In nature, most orchids grow new roots when the growth of new leaves
begins. For orchids with rhizomes, this usually happens when a new
growth is maturing. For orchids that grow from a central stem, e.g.
phalaenopsis and vandas, new roots are associated with the onset of the
rainy season or warm weather. Thus, your orchids should be getting new
roots right now.
There are some things that can prevent an orchid from growing roots,
including insects and disease. If you have an orchid will not grow new
roots, especially if it was just repotted, then some action may be
necessary to stimulate new root growth and save the orchid plant. An
orchid without roots will eventually die.
The first question to ask is whether the problem orchid is a species. If
that is the case, then a quick check with an appropriate book will tell
you if there are special issues with respect to new roots for that
species. Many of the large bifoliate cattleyas, e.g. C leopoldii and C
bicolor have specific times when they grow roots. These should be
repotted only when they are about to get new roots.
If your orchid is not a species or a species with no specific rooting
issues then a check of the plant is necessary. Are there currently live
roots on the orchid? Are the leaves wilted or shriveled? If there are
many live roots, but leaves are shriveled then look for insect pests.
Scale insects, mites, and mealy bugs can all suck enough liquid from a
plant that has good roots to cause desiccation of leaves. You may need
to take the orchid from the pot, look under leaves and even check the
living roots. Don’t be hesitant to use a magnifying glass because some
of these “beasts” are tiny. If you just find one it is a good bet there
are more and this is the problem.
A fine jet of water can be used to remove scale from the leaves, under
roots and even between leaves. My preference is to follow this procedure
several timers from different angles to be sure all are removed. It only
takes one to regenerate a whole new colony.
If most of the roots are dead then the issue is likely either disease or
decaying medium. Using the same fine water jet, wash the entire plant
thoroughly and let it dry. If there are soft spots on the rhizome or
stem apply 2% Hydrogen Peroxide, the stuff you have in your medicine
cabinet. After 15 minutes, soak the entire plant, not just the roots, in
the recommended concentration of “Root Tone” or similar hormonal
stimulant. Some orchid books maintain that orchids do not respond to
such a treatment, but they will. Soak for 15 minutes and then let dry.
Next keep your orchid in a shady location. For me they go under the
bench. Some growers that have humidity issues will remove all dead
tissues and place the plant in a clear plastic bag under the bench until
new roots appear. It is necessary to be sure no water accumulates in the
bag. Once new roots appear repot, but keep the orchid under lower light
until there are enough roots to anchor the plant in the pot. Then it can
be slowly moved into its normal light regimen.
Getting vandas to grow roots can also be an issue. Members of the vanda
group will occasionally become very leggy and refuse to grow roots on
the stem, resulting in large plants with leaves at the top, roots at the
bottom and a long stem in between. Find a long plastic window box that
will hold the root mass and as much of the stem as possible and soak in
“Root Tone” for 30 minutes. Place back in its normal location and wait.
Typically, new roots will emerge from what looked like a dead stem.
After these roots get 2-3 inches long you can cut just below these new
roots and repot the top portion. Within a few weeks the lower part of
the stem will sprout new leaves and you now have two plants.
