Repotting Orchids
Orchid Repotting: A Beginner’s Guide
Some things to keep in mind before you start
The Ingredients of a Basic Cattleya Mix: From left to right: “Sponge Rok,” redwood Orchid Bark, coconut husks.
First off, relax! Unlike other plants, your orchid won’t begin to shrivel up the moment it’s out of its pot. As a matter of fact, most orchids need their roots exposed to the air if they’re to grow properly, so you can take your time and do the job right. If for some reason you’re interrupted and have to be away for more than a few hours, just cover your orchid’s roots with a damp cloth.
Cleanliness: You won’t exactly be performing surgery, but you will be breaking a few roots and cutting into your orchid plant if you’re dividing. Orchids are prone to viral infections that,
for all practical purposes, are incurable. These viruses may not kill your plant, but they will damage it by deforming the leaves and flowers, causing color-streaking in the blooms and forming brown, lace-like whorls on the leaves that will never go away. In short, your possibly expensive plant will become absolutely worthless. Don’t risk it! Up-pot into new containers only, and sterilize any cutting instruments by soaking them in a solution of 1/2 cup bleach or Physan to 1 gallon of water for 10-15 minutes and letting them air-dry. Or, you may pass them through an intense flame. (A plumber’s
All Set to Repot: From left to right: potting mix, pruning shears, wire plant tie, lava rock, bamboo stake, and orchid pot with slits for air penetration.
soldering torch is excellent for this purpose.) Wash your hands well before you begin. If you’re a smoker, Tobacco Mosaic Virus can be present on your fingertips so rinse your hands in the bleach and water solution after washing! If these precautions seem excessive to you, consider that in some tropical, foreign countries, many wholesale, government-subsidized orchid growers with millions of dollars’ worth of plants at stake insist that their employees use latex gloves when repotting plants and that they change their gloves before every new plant they begin to work with to avoid cross-contamination. So: you’ve been warned. Always wipe your work surface clean before you begin, again using the bleach-water solution. If you’re repotting more than one plant, wipe your work surface after each plant that you do.
What you will need: 1) A new pot large enough to sustain two years’ worth of growth. A pot that’s too big won’t allow the medium to dry enough between waterings and your orchid’s roots will be much more prone to rot. 2) Orchid Bark or another type of specialized orchid mix. These are formulated using redwood bark supplemented with a combination of charcoal, perlite or “sponge-rok,” chunk peat, oyster shell, coconut husk, and other materials mixed in various combinations and quantities depending on the type of orchid being grown. Plain orchid bark can be found at most quality nurseries. 3) Sanitized clay pot shards or lava rock for covering your pot’s drainage holes. Styrofoam “peanuts” (the NON biodegradable kind) commonly used as shipping protection may also be used for this purpose. 4) Sanitized pruning clippers or a sharp, sanitized knife. You will use these to divide your plant or trim any roots that are dead or have grown too long to fit in the pot. 5) A bamboo stake and wire plant tie. These are essential for holding your newly potted plant steady until its roots grow enough to anchor it in place on their own. 6) Pruning sealer or anti-fungal powder. If you’re dividing, a thin layer of this on any open cuts on the rhizome will help prevent fungal rot.
Waiting Too Long: If you repot when roots have already established themselves aerially, you run the risk of destroying the entire new root system. In this case, wait a little longer until new shoots begin to protrude from the current growth and repot then.
The best time to repot: Most growers (ourselves included) repot in late spring and early summer before the onset of vigorous new growth. Since roots that have been growing exposed to the air for any length of time will most likely die when packed beneath the bark surface, try to repot just as new growth is beginning to appear. If you waited too long and your plant is already well into its new season, hold off until after your orchid has bloomed, otherwise you will lose that growth’s flowers and you’ll run the risk of killing the plant’s entire new root system. Repotting should be done every year-and-a-half to two years, before the potting medium begins to break down into peat and loam. Waiting longer than two years allows the broken-down medium to retain too much moisture, keeps the roots from receiving any air circulation, and will contribute to the onset of root rot.
The day before you repot: Water your orchid thoroughly. A good watering the day before will make your plant’s roots pliable and much easier to work with. Soak your bark or mix in a container of water overnight. The mix will absorb moisture, and soaking allows it to be packed more firmly around your plant’s roots.
Ask a grower your specific repotting question at the Orchid Forums of RVO. We are here 24-7 to help you grow your orchids better!