We examined changes that occurred in acorns during storage at different temperatures and moisture contents over a period of 3 y. In general, we found that to achieve optimum viability, acorns must be stored fully hydrated. Acorns also survived longer and sprouted less while in storage if stored at -2 °C (28 °F) instead of the usual 4 °C (39 °F). However, we suspect damage to white oak embryonic axes at the lower temperature and at this time cannot recommend storage at -2 °C for this species. While we were able to store fully hydrated red oaks for as long as 3 y, we have been less successful with the white oaks. If you are in doubt about the quality of your acorns, go back to the basics—clip open a sample and check them for color and freshness.