I have an avocado tree that is about three years old and about 20 inches high. I put it outside every summer and bring it in for the winter. This fall when I brought it in it was healthy, however all winter I have been struggling with drying leaves. It starts almost immediately as the leaves form as browning on the edges. They slowly dry up from the edges to the stem and then fall off. Has anyone had a similar problem? It is dry in our house, as we do not run a humidifier, so I am suspicious this may be the problem.
It does sound like an issue of low humidity or possibly under-watering. Is it drier in the house this year than it was the previous winters? Avocados need at least 50% humidity to do well. If you can't get a humidifier (I found a 1950's model last fall at a 2nd hand store and it works perfect!) you could try setting the container in a large saucer filled with stones and water....container sits on stones and not in the water of course...and see if that helps a bit. Also get a mister/spray bottle and mist it often. Could also try double potting; where you stick the container into a larger pot that has been filled with sphagnum moss on the bottom and sides...the rim of the larger container should come up above the one inside. The sphagnum moss should be kept moist at all times to help bring up the humidity. Lastly what size pot do you have it in? Have you checked to see if it was root bound? If there are more roots than soil it might not be getting enough water. Since you don't describe yellowing and wilting of the leaves I think of under-watering vs. over-watering. Avocado don't like to be dry, but also don't like to have too wet conditions either where they will rot. Most plants require less watering over the winter because they are less active, however if the humidity in the home is pretty low watering requirement will be higher. Good luck :)
If your plant has not been repotted over the three years, it is now time to do so. Remove as much of the old soil, and pot up. I have a trouble free one year old plant, and it is semi dormant but I keep it from drying out, and in a SW window. Once the temperatures and daylight increase the growth can be rapid. I had one grow one metre, when planted out of doors for a summer....they love heat!
