[Previously posted on Practically Gardening]
Every winter I get questions about the leaves of houseplants drying out. A good part of that is the low humidity in our homes in winter. Once the windows close and the heat clicks on, the moisture level plummets.
Houseplants need less water during winter. Most actually go semi-dormant, although they remain green. However they still need some water. You don’t want to leave the soil bone dry or run into the problem of the soil pulling away from the sides of the container, allowing all the water to run out the bottom before soaking the soil.
Okay, but I Do Water and They Still Dry Out
Assuming you are watering and your plants are still getting dried out leaves, the problem is usually insect pests. How these little buggers can find a plant that is safely tucked away in your living room has always boggled me. Yet they can.
If your plants have been vacationing outdoors for the summer, you need to inspect them really well for hitchhikers. Even then, I always spray mine with insecticidal soap or neem, just because. But I am not militant about it and inevitably some determined thug will find its way inside.
Specifically What Am I Looking For?
The most likely culprit is spider mites. For an insect most of us never see, they are quite abounding. When they attack, leaf color tends to stipple a little, while drying. You should also see thin webbing, especially under the leaves. Look around before you take action. The webbing could be a spider, an ally against pests.
But if it is spider mites, you can wash them off with water. It will take a few tries to get the ones that hide out. I generally reach for my neem again. You have to stop them early.