Q. Last year I grew an avocado outdoors from its pit. As the temperatures began to dip I transplanted it to a pot and brought it inside. The older leaves have begun to turn brown and dry up. I fertilized it once since bringing it indoors. I water it lightly every other day as the leaves begin to curl up due to lack of water.
A. The main reason leaves drop from an avocado brought inside is the change in light intensity or duration. Moving it from a soil to a container can cause leaf drop as well. Leaf drop can be caused by a watering problem. A fourth possibility are pests like mites.
|Avocado. Picture from the California rare fruit growers.|
Plants grown outside develop a different type of leaf than plants grown inside. The change in light intensity causes leaves grown outside, called sun leaves, to drop. The plant begins to add new growth with a thinner, larger leaf called a shade leaf.
Disruption of the root system can cause leaves to drop. We call this transplant shock. It is also possible that the change in watering could cause leaf drop. Avocados are prone to mite problems so if there are mites on your interior plants it’s very possible they were transferred to the avocado.
What to do? Make sure the avocado gets as much sunlight as possible. A south facing window is probably best. You need to provide several hours of sunlight to keep it healthy and prevent it from becoming spindly.
|Spider mite damage on interior foliage plant|
Water the soil in the container until water comes out the bottom. Do not water again until you can feel a dramatic change in the weight of the container. Another method to judge the moisture in the soil is to use a pencil or soil moisture meter.
Push a pencil in the soil and see how easily it pushes down. A pencil is more difficult to push in dry soil than wet soil. You will feel the end of the pencil after you remove it to see how moist it is. A third method is to use a soil moisture meter you can purchase at any nursery or garden center.
Mites are common problem for avocado. There are two methods you can use to inspect the plant for mites. First, take a white piece of paper and slap a yellowing leaf against its surface. Pick up the piece of paper and look at it carefully under a bright light.
If you have good eyes or a magnifying glass you’ll see very small mites the size of a pencil dot crawling along the surface. You can also drag your fingers lightly across the surface of the paper and the mites will leave a red smear.
Use a horticultural oil and spray the plant from head to toe to suffocate mites. Oils work well against active mites as well as soap sprays.