Acorns sprout, or germinate, between two and four weeks after they are planted. Some acorns will begin to sprout before they even fall off the tree, though not all acorns sprout.
Weevils and animals such as deer, scrub jays and squirrels eat acorns that have fallen to the ground, resulting in the loss of many otherwise healthy acorns. Acorns that lose some of their moisture due to dry weather or dry storage are far less likely to sprout. Acorns that have not yet sprouted may never sprout at all if they are left lying on dry ground for several days.