Repotting Orchids: Tips and Tricks

Repotting Orchids: Tips and Tricks

Repotting orchids is vital to their long-term survival and their ability to bloom. Whether your orchids outgrow their pots, the nutrients in the medium are depleted, or the potting medium decays, it will eventually lead to disease, malnourishment, and stagnating growth. The two most common potting mediums, bark, and sphagnum moss each have their benefits. Bark lasts longer and drains better. Sphagnum moss retains water better, and has antifungal and antibacterial properties, but doesn’t last as long. Bark lasts approximately two years; sphagnum moss lasts roughly a year. The goal when repotting is to choose a correctly sized pot, and replace the old potting medium with new, while avoiding harm to the roots.

When to Repot
The ideal time to repot your orchid is before the current potting medium begins to break down, and when new roots are emerging that have not yet attached to the old potting medium. Orchids adjust to a new pot and potting medium very quickly when they have new roots to push into the medium and take hold. If repotting is already long overdue, it is better to do it than to wait for new root growth, especially since repotting often stimulates orchids to grow new roots. 

Set Up
Before you begin repotting, prepare a table with newspaper, or another means of keeping the mess contained. If you are repotting your orchid in bark, estimate how much you need and rinse it thoroughly prior to use. If you’re repotting with sphagnum moss, wet it slightly until it is moist, pliable, and fluffy. If your sphagnum moss feels heavy and soggy, squeeze out excess water prior to use. 

Removing Orchid from Old Pots
If the pot is made from a flexible material like plastic, give it a slight squeeze around the outer walls to help loosen the medium and roots. Orchid roots release more readily from smooth surfaces like plastic and glazed ceramic. If the pot is rigid and porous, as in the case of terracotta, wet the roots, the potting medium, and the ceramic itself before attempting to remove your orchid. Hydrated orchid roots are more flexible, and release more easily from the sides of a terracotta pot. Sliding a smooth, thin object like a plant ID tag along the inside of the pot can help part orchid roots from the clay. When you are ready, angle the top of the pot downward toward the newspaper, and gently pull to release your orchid from the pot. 

Preparing Roots
Examine the roots. Hollow or mushy roots should be trimmed off and discarded; roots that feel firm are alive. Rinse off any dust or potting material that remains attached to the roots; once wet, the roots will be easier to work with, and less likely to crack or break. 

Pot Size
Once the roots are cleaned up, choose a replacement pot based on the size of your orchid’s root system. If your orchid’s root mass increased in size during its time in the previous pot, choose a new pot that is an inch or half-inch larger. At most, we only want to accommodate another year or two of growth. Orchids require ample oxygen at the roots, which is better served by pots smaller than you would use for terrestrial houseplants. If your orchid’s root system has remained roughly the same size, you may continue growing it in the same size pot. If you’re unsure which size pot to choose, a good ratio of orchid roots to potting medium is 50:50. Pots too large have too much potting medium, which cannot exchange oxygen sufficiently, resulting in a soggy, stagnant medium that causes root loss and disease. 

Repotting Orchids in Bark
If your orchid has roots longer than the pot is deep, you may need to gently turn your orchid (in a loose corkscrew fashion) to fit the roots as it descends toward the pot. Roots may kink or crack as you tuck them in, but it won’t cause lasting harm. When repotting your orchid into new bark, add the medium to the pot while holding your orchid in place. When you’re finished, the base of your orchid should be roughly flush with or slightly above the potting medium. A small portion of the roots where they emerge from the base of your orchid will likely be visible once you’re done repotting, which is normal. As you fill in the space around the roots with bark, tap the sides of the pot, or shake it gently while supporting the orchid to help settle the bark in place. Once the pot is full of bark, check to see if your orchid is stable. Orchids that are loose, or wobbly in their pots tend to languish. If your orchid doesn’t seem anchored in place, press gently but firmly on the bark at the top of the pot, which will lodge it against the medium beneath, and the walls of the pot, creating more stability.

Repotting Orchids in Moss
Begin by lightly wrapping moist sphagnum moss around the roots of your orchid until you have a mass of moss that will fill the pot. Wrapping the roots in moss before placing your orchid in its pot will ensure there aren’t empty spaces in the bottom of the pot; it also snugs your orchid in its new pot, providing stability. You may need to add or remove sphagnum moss before your orchid slots into the pot correctly. You want it snug, but it shouldn’t be so tight that you have to force the sphagnum-wrapped roots into the pot. 

After Repotting
Repotted orchids benefit from a period of adjustment to their new pot. Withhold water from your newly repotted orchid for 3 to 5 days. Since you rinsed the bark, or hydrated the sphagnum moss prior to repotting, there will be sufficient moisture in the medium for this brief rest period.

Spiking, Budding & Blooming Orchids
When possible, refrain from repotting orchids that are in bloom, spiking, or in bud. Before we delve further, let’s define these terms. Orchids that are spiking, or “in-spike” are in the process of developing the stems (called inflorescences) that carry the flowers. Orchids that have unopened flower buds on those “spikes” are “in-bud.” Orchids with open flowers are, not surprisingly, referred to as “flowering,” or “in bloom.”  Repotting can be a short-term hardship for your orchid, depending on its condition when you repot it. If your orchid is already devoting energy to the growth of spikes, buds, or to sustaining open flowers, it may have little energy to spare. Repotting orchids during such an energy-demanding period can pose enough strain that flowers, buds, or inflorescences stall or fail. 

If your orchid is in drastic need of repotting and happens to be in spike, in bud, or flowering, follow the repotting process described above. Carefully clean away the old potting medium, remove dead roots, and take extra care to avoid damaging healthy roots. Orchids that are spiking, or that have small buds forming are more tolerant of repotting than orchids with large buds, or open flowers. Large buds and open flowers are at far greater risk of wilting and falling off after repotting. 

If you repot a spiking, budding, or flowering orchid and discover significant root loss, or other evidence of disease or distress, you may wish to take an entirely different approach. Regardless of the problem, you may wish to remove the flower spikes from your orchid so it can redirect energy to survival. As discussed above, flowering is an energy-demanding process. A distressed or diseased orchid that undergoes flowering may recover after that process is complete, but the odds of a full recovery are increased if your orchid is spared from diverting energy to flowering.