you get 30 coconuts every I think it's 4 hours. However long it is between crops regrowing. I good trick to harvest more crops is to wait till you have 2 or 4 left. Since they take back 4 at a time, this will be only one more trip. Also, even if they only get 2, it adds 4 to the bin. Anyway, the trick is, the game won't take the coconuts out of the tree until they are put in the bin (that way you won't loose food if they drop coconuts). So once you are down to one trip left, bring every working villager over to the trees. Since the coconuts aren't taken out of the tree until it reaches the bin, each villager manages to bring back 4 coconuts. It's like Jesus with bread and fish.