Q.Indoor avocado plant
I started my avocado plant from a pit in February 2017. I had it growing in an 8 inch pot and when I noticed new growth about a month ago, I re-potted it in a 10 inch pot with fresh cactus potting mix. I watered it the same day, and since then it has not looked good. The leaves have become crisp and curled inwards and the new growth at the top seems to be dried out and dying. The soil appears to still be moist so I did not want to water anymore. (The brown spots on the lower leaves in the photos are older and were there before re-potting) Any advice is much appreciated!
Certified GKH Gardening Expert
There are many things that happened here. These, either, need a rather large container, of about 8 gallons or more, or constant root pruning. I notice the severe stretching, which will indicate that it needed more light. These are light starving trees that will tolerate even stronger light than the sun can produce, so as much as you can give them the better they will do. Ideally, you will want to keep a target distance between leaf nodes at about half an inch between the ones above and below. This will mean that it is receiving the proper lighting.
The proper potting mix will be necessary as well. This mix contains very little to no nutrients. This means that once the seed shell has fed the tree until it falls off, there will be nothing left for the tree to feed on. In response, it will stretch, shrivel, dry up, and die very quickly.
This will need a very heavy potting soil with added compost in a well draining container. Dolomitic lime will help keep the pH to a suitable level.
You will also need to know the sex of your tree, as it will need a separate tree of the opposite sex to produce fruit.
At this point, it will be best to start fresh, and put it under horticultural lighting as soon as you see activity from the seed.
This article will help: https://www.gardeningknowhow.com/edible/fruits/avocado/avocado-tree-growing.htm