change few growing to nil and lettuce/cabbage drops

crops/blackberry.lua

@@ -42,7 +42,7 @@ minetest.register_node("farming:blackberry_3", table.copy(def))
 
 -- stage 4
 def.tiles = {"farming_blackberry_4.png"}
-def.groups.growing = 0
+def.groups.growing = nil
 def.drop = {
 	items = {
 		{items = {'farming:blackberry 2'}, rarity = 1},