TheNaturePlanet

"It's autumn, and the roots of my Phalaenopsis orchid look messy—should I prune them?" There isn't a definite answer, but it's generally okay to prune, as long as you can tell the difference between "roots that should be pruned" and "roots that should be left alone." If you're not careful, cutting the wrong roots might result in the plant's death.

Why is root pruning often mentioned in autumn? During the summer, high temperatures and humidity can cause the roots of Phalaenopsis orchids to either rot from being trapped in the pot or decay due to overwatering. When autumn arrives and temperatures cool down, it's the perfect time to clean up rotten roots. After pruning, the temperature is moderate, allowing the roots to recover quickly, and it prevents bad roots from spreading further, giving the orchid the energy to bloom in winter. However, if the roots are healthy, avoid unnecessary pruning, as good roots are essential for water and nutrient absorption, and cutting them will hinder growth.

So, which roots should you prune? Here's an easy way to tell: Gently remove the orchid from the pot, don’t pull too hard. Use your hands or a small brush to clean the moss and bark from the roots, then inspect each root!

Rotten roots: These will feel soft, and when squeezed, they'll collapse. The color will usually be brown or black, and some may even ooze a sticky liquid that smells musty. These roots only consume nutrients and may cause healthy roots to rot, so they should be pruned.

Hollow roots: These look white but feel empty and lack a firm texture. These are dried out from lack of water and have lost their ability to absorb nutrients. They take up space and should also be pruned.

Old, black, and brittle roots: These roots break easily when touched. They should be pruned to make space for new, healthy roots to grow.

However, healthy roots should not be pruned. If the roots are white, plump, and firm to the touch, or slightly greenish and translucent ("crystal roots"), leave them alone. Even if they look messy, these are the essential roots that keep the orchid alive. Cutting them will reduce the plant's ability to absorb nutrients, leading to yellowing leaves and lack of flowers.

When pruning, use garden scissors, not kitchen scissors. It's best to disinfect them with alcohol or sterilize them by heating the blades with fire to prevent infection at the cutting site. Prune at the junction between healthy and unhealthy roots, leaving no decayed tissue. After pruning, don’t pot the orchid immediately. Dip the cut ends in a fungicide powder and let the cuts dry in a well-ventilated, shaded area for a few hours to prevent bacteria from entering.

When repotting, use fresh planting medium, such as moss or bark. Old materials may harbor bacteria, so don’t reuse them. When repotting, don’t bury the roots too deep—it's okay for part of the root to remain exposed. Phalaenopsis orchid roots need air to breathe, and burying them too deep can cause rot.

Pruning roots in autumn is not a mandatory step but rather a solution to a problem. If your orchid’s roots are strong and healthy, with no rot or hollowness, just water and fertilize as usual and wait for it to bloom in winter. Only prune if you notice problems with the roots. Many orchid enthusiasts make the mistake of pruning healthy roots out of habit, and end up killing their plants—such a shame.