Question
Hello Tom,

Thanks Again for the taking the time to read and reply to all the emails you must receive.
On the subject of planting a rooting avocado into a medium.
I have three currently in suspended in water. One has sprouted so far. How long is okay to wait before transferring to soil? I was hopeful to see an actual seedling before I made the transfer.
When you say, 3-4 inches deep for the seed of an avocado. You mean below soil level entirely, dig down three-four inches, place seed and cover with 3-4 inches of top soil?

Thanks Again Tom!

Christopher Joe in Largo (Soon to be the Avocado Capital of the World)

Answer
Hey Christopher Joe,
I love Key Largo!  It would be great if you made it the avocado capital of the world.  Good luck to you.  I would plant my avocado seeds as soon as you see evidence they have sprouted such as the beginnings of a root at the tip of the seed.  Don't let the root get too long or a green sprout to get large.  Reason?  You run the risk of breaking a fragile root.  Plant in a large pot and plant deeply.  Don't worry about seeing the actual seedling, be concerned about planting the rooted seed.  The rooted seed will sprout quickly as long as you keep the soil warm (70-80F) and a moist environment (humid).  The sprout will appear quickly once the root is in a warm environment.  I hope this helps.
Tom