Compost is an item used most commonly with the Farming skill. While not as effective as supercompost, it reduces the chance of a player’s crops becoming diseased (1:4 ratio) while growing throughout the plant cycle, as well as increasing the minimum and maximum number of crops that will be received by the player upon harvest.

It can be made by putting weeds, sweetcorn and other farming produce into the compost bin at farming patches. It takes 30 minutes for the bin to make it rot into compost, but when it is finished rotting, the bin fills 15 buckets with compost. Filling a bucket with compost gives 4.5 Farming experience. Applying a bucket of compost to a farming patch gives 18 Farming experience. Compost can also be bought from farming shops, such as those near the cabbage patch south of Falador, and Alice’s Farming Shop north-west of Port Phasmatys.

Three buckets of compost can be used as payment for a farmer to watch over barley seeds as they grow, or two buckets for potato seeds.

Compost is also an ingredient used in creating sulphurous fertiliser, along with saltpetre, to gain favour in Hosidius House of Great Kourend. 5.0% favour in the Hosidius House is required to create sulphurous fertiliser.

Compost can be upgraded into supercompost by using one dose of compost potion on either a bucket of regular compost, or a compost bin filled with regular compost.