Palm care

Asked December 3, 2019, 11:58 AM EST

I’m wintering a neighbor’s palm in my heated basement and have trouble gauging how much and how often to water it. This morning I noticed some damage to several frond ends. Can you offer advice?

Montgomery County Maryland

1 Response

There are a few environmental (as in, not pest or disease) conditions that could be contributing to this leaf damage. Indoor humidity is often quite low in homes with central air in our area. While basements do tend to have higher humidity than other parts of the house, it's quite likely that in winter it's still much too dry for most tropical houseplants to prosper. Misting is often suggested to raise humidity around plants, but a more effective tactic is using a room humidifier (to the benefit of the humans at home too) or at least a "humidity tray" with something (often pebbles) to suspend the pot above the water line in a saucer of water. Be careful that the water level isn't high enough to be absorbed by the soil in the pot's drainage holes, though, as this will lead to root drowning and death.

Buildup of salts can occur in potting soil that hasn't been refreshed in several years. Minerals from fertilizers and "hard" tap water as well as added water softeners can bind to the soil and build up to damaging levels over time. In that case, repotting the plant with fresh potting soil is best. If you are fertilizing the palm, discontinue until spring, when it resumes active growth.

As far as how much and how often to water will depend on how often it's drying out. It's best for many houseplants to reach at least partial dryness between waterings; in this case perhaps 2" beneath the surface, though it may depend on how root-bound it is and what kind of soil it's in. There is no hard-and-fast rule about dryness levels, but aim for somewhere between constantly moist and fully drying between waterings. When water is needed, thoroughly soak the soil so that excess drains out of the bottom of the pot, and make sure the saucer is emptied of water so it can't soak back into the soil afterwards. In this way you can be sure that all of the soil has been wet-down so the lowest roots don't dry out, as they might with lighter doses of water.