Sandy Piles fully regrow after around four days (one tier every two days) during Mild Season and Dry Season. During Hurricane Season and Monsoon Season, they require double the time for regrowth. According to the game files, Some other rare drops can be obtained from Sandy Piles. Those items and their drop rates are Seashells (1%), Rocks (1%), Feathers (1%), Gears (0.2%), Red Gems (0.2%) Dubloons (0.2%), Venom Gland (0.1%), Coconuts (0.1%), Purple Gems (0.1%). In addition, Crabbits and Snakes each have a 0.1% chance of spawning.