About 24 hours, but it depends on what you are freeze drying. If it is something very juicy or thicker, it could take longer. If it drier and/or in smaller/thinner pieces, it could take less.

I love my freeze dryer. I don't know if I've gotten my money's worth yet (I have used it a good bit), but it has been fun and I am freeze drying higher quality stuff than what you can normally buy in a store.