What should you do if a Phalaenopsis (moth orchid) has some roots rotted from overwatering?
The most headache-inducing thing about Phalaenopsis is watering. Many flower lovers have stepped in the same pit: afraid it will get thirsty, they pour water into the pot every few days, and as a result a perfectly good orchid ends up with rotted roots from watering. In fact, Phalaenopsis roots really do not love drinking that much water; too much water will definitely cause root rot, and it rots fast - in three to five days it can make you stomp your feet in distress.
Why does too much watering cause root rot? Phalaenopsis roots are the plump kind of aerial roots, wrapped on the outside in a silvery-gray film. This film did not grow for nothing - it can both absorb water and let air through. If you water too much, the water in the pot cannot drain out, and the roots sit soaking in water. After being soaked for a long time, that film wrinkles and turns transparent, oxygen cannot get in, and bacteria start having a party inside. Within a few days the roots rot into a sticky brown mass, and when you squeeze them they still ooze water - just looking at it is depressing.
So if you accidentally overwater and find that some roots have rotted, what should you do? Do not panic - if you rescue it quickly there is still time. The first step must be to take it out of the pot. Gently remove the Phalaenopsis from the flowerpot, being careful not to break the good roots. Then find a clean place and cut off all the rotted roots - remember to use disinfected scissors; household scissors just need to be wiped with alcohol. The rotted roots must be cut off thoroughly; anything that looks blackened or soft cannot be kept, until healthy white or light green roots are exposed.
After cutting the roots, do not rush to repot; you must disinfect the wounds. The simplest way is to find a packet of carbendazim, mix it with a little water into a paste, and soak the roots in it for 10 minutes, or directly use a cotton swab dipped in carbendazim to apply it to the wounds. After that, place the orchid in a ventilated, cool place to dry for at least one day, letting the wounds form a protective film. Do not skip this step, otherwise if you replant the damp roots, it is like throwing another party for the bacteria.
After drying, you need to change the pot and the growing medium. The original flowerpot and sphagnum moss definitely cannot be used; they are full of bacteria. It is best to switch to a breathable plastic pot with several extra holes punched in the bottom. For the growing medium, use new sphagnum moss. After soaking it, squeeze out the excess water; the degree where you can feel moisture when holding it in your hand but no water drips is just right. When repotting, do not pack the sphagnum moss too full; just loosely wrap it around the roots and let the aerial roots breathe freely.
After handling it, do not water for the first half month; just keep it in a place with diffused light, such as by a window behind a sheer curtain. When you see new roots emerging, or the leaves look a bit more lively, then use a spray bottle to lightly mist the sphagnum moss with a little water. Remember, Phalaenopsis is not afraid of dryness, it is afraid of waterlogging. Usually before watering, first feel the sphagnum moss; water only when it feels dry and hard. Also, water slowly along the edge of the pot, and do not pour it into the leaf core or onto the petals, otherwise not only will the roots rot, but the core may rot too.
When growing Phalaenopsis, less water is always better than too much. If you really do accidentally cause root rot, do not be afraid; rescue it in time, patiently wait for it to recover, and after a while it will still bloom beautifully for you.