You can start the pits in damp potting soil as well as in water, so you could probably put it in a pot now, with just the upper part of the pit sticking out (just barely). I would think a 6" diameter pot would be about right. You can always repot it into a larger pot later on.

So the shock of being in a drier environment doesn't kill it, I would put a clear plastic bag over the newly-potted pit, but cut some holes in it for ventilation, and enlarge them when the top starts growing, then leave the pot uncovered for air movement. All you would need would be some mold or fungus to start.

I would also put the potted pit in indirect light to encourage the stem to start growing, although it may grow well behind (time-wise) the root, like an acorn does.

Once you've got some leaves, I would feed it with some diluted worm tea or apply a thin (1/8") layer of good homemade compost to the surface of the pot and water it in.

Sue

I agree with her. Put it in a small pot and keep the soil moist. I personally would use miracle grow potting mix. Holds moisture and is full of nutrients for the plant. I had an avocado seed in a very small pot with some native sandy soil under the shade of a banana tree and when it was about 4 inches tall, I planted it in partial shade area in an existing hole where other my banana tree was. That was back in May of 2008 and now it is 7ft tall. I live in a rocky landfill area of southeast Florida.