Grain is obtained by selecting 'Pick Wheat' in wheat fields growing in many places in RuneScape. They are also dropped by goblins and imps. It is used for Cooking.

Wheat fields are found:

One quick way is to get grain next to the hops patch in Yanille and go east to the bank in Yanille. Another is to get to grain is to use the canoe transport system on the River Lum. One could take the canoe to the Champions' Guild wheat field, then fill their inventory, then return to Edgeville to bank the wheat using the canoe. The wheat fields are also used to access Puro-Puro.