Minecraft wiki entry for Snow_farming, associated text: To operate the farm, the player will need one or more shovels and inventory space sufficient to collect a lot of snowballs. Note that snowballs only stack to 16. However, 4 snowballs can be crafted into snow blocks, which stack to 64, and yield the 4 snowballs used to craft them when mined. So, if you're running out of inventory space, you can craft the snowballs into snow blocks. Later, when you are ready to use the snowballs, place the blocks on the ground and mine them.