How to Tell if Your Compost is Ready

Dan This Land of Ours


In today’s program, Cathy Isom has some valuable information about how to tell if your compost is ready.  That’s coming up on This Land of Ours.

How to Tell if Your Compost is Ready

Composting is one way many gardeners recycle garden waste. Shrub and plant trimmings, grass clippings, kitchen waste, etc., can all be returned to the soil in the form of compost. While seasoned composters know from experience when their compost is ready for use, newcomers to composting may need some direction.

There are many variables that contribute to the timing of finished compost. It depends upon the particle size of materials in the pile, how often it is turned to supply oxygen, the moisture level and temperature of the pile, and the carbon to nitrogen ratio. It can take from one month to a year to achieve a mature product, factoring in the above variables, plus the intended usage. For example, to use compost as a top dressing takes the least amount of time.

Finished compost, or humus, is needed to use it as a growing medium for plants. Unfinished compost can be detrimental to plants if it is incorporated into the soil before it reaches the humus stage. Finished compost looks dark and crumbly and has an earthy smell.

There are scientific methods of testing the compost for maturity, but they can take some time. The quickest method is to place some compost into two containers and sprinkle them with radish seeds. If 75 percent of the seeds germinate and grow into radishes, your compost is ready to use. More complicated methods of calculating germination rates include a “control” group and can be found on university extension websites.

I’m Cathy Isom…