I have finally convinced myself of the best practices for watering the poor Avocado plant, from experience. Opinion on this varies widely, from what I read online. Some say that the avocado should be let to dry out completely, then soaked thoroughly until water drains out the bottom. One site even suggested that without this regular soaking the plant would ultimately die. Others suggest consistent moisture. But I have found, from alternating methods in an attempt to make my plant happy, that I agree with neither one.
Too much water seems to make the leaves nice and upright but wavy on the margins, as here when I kept it damp enough that mushrooms grew!
The let-dry-out and then give a heavy soaking method makes mine droop. I realized this just recently when I switched from infrequent soakings back to giving it smaller amounts of water two or three times a week. Maybe a cup or two. The sides of the clay pot dampen, but it doesn't drain out the bottom and have to get emptied (a difficult task anyway with such a large pot). The plant seemed to be doing better and the new leaves looked very healthy. Have quickly grown to almost full-size. Then I forgot one day and gave it more water than had been the norm. Later that day I noticed that the newer top foliage had begun to curl under and droop.
So now it looks like this: