How Long Do Corn Cobs Take To Compost?

When it comes to summer crops, corn is everywhere: in fields around us, in some of our backyard gardens, and if you don’t grow it, you might purchase ears for dinner throughout the season. However you come across them, corn cobs and husks create a lot of food waste that you can take advantage of in your compost pile.

Depending on how hard the cobs, husks, and stalks get, as well as the type of compost system you have, corn scraps can take anywhere from 6 months to a year to decompose. In some situations, it may create a good slow-release organic fertilizer or hearty mulch, and in others, it might create compost that has just too much-unfinished bulk.

In any case, corn cobs and other scraps will break down with time and provide a range of important nutrients as a compost ingredient.

Can You Compost Corn Cobs And Husks?

Corn cobs, husks, silk, and stalks are all organic matter that can be added to your compost, but they may have to be treated differently based on how dry they are and the type of compost system you have going.

When cobs and other corn materials are still green, they’re full of moisture that allows them to be broken down quickly by nitrogen-loving bacteria. When these materials have dried and are brown, they become hard, woody, and dense and aren’t easily broken down.

The dry corn material stays in compost much longer than moist green material and is among the last materials to be broken down by fungi in the second part of the decomposition process.

When you add corn husks, silk, and stalks to compost when they’re green, they have to be balanced with brown material like dry leaves, cardboard, and sawdust. The carbon and lignin-rich cobs take a long time to break down, even when they’re added fresh.

When cobs, husks, and particularly stalk dry out, they become very hard and must be balanced with green material, like food scraps and fresh yard cuttings, and grass clippings.

Are Corn Cobs Good For Soil?

Corn cobs are good for soil when they’re part of finished compost, but they shouldn’t be applied until the solid materials are unrecognizable in the compost. Too fresh of material just doesn’t mix well with your soil, which should be a very fine and crumbly consistency. Large, unfinished pieces of compost might start to rot or attract mold if applied too early.

As these large pieces continue to break down and disappear, they can create air pockets in the soil, which will lead to an uneven surface level, which can lead to compaction in some areas.

The best way to make sure your corn cobs are completely decomposed is to, first, add them to the compost in the smallest pieces possible, and second, to give the amount of time necessary for the compost to finish breaking down all of the materials in the heap.

Pile of Corn Cobs

What’s The Best Way To Compost Corn Cobs?

Cutting or snapping corn cobs in half before adding them to your compost heap helps them break down more quickly, and it’s even better to be able to put them through a wood or garden shredder if possible. The smaller the pieces, the more even the resulting compost will be.

When it’s finished, you shouldn’t be able to recognize the corn material within the compost, which will be dark brown, almost black, with a crumbly yet moist texture.

Corn cobs can be composted in any method, but they will have to be treated differently based on the material’s dryness. If the husks, silk, or stalks are fresh, they can be added to brown, carbon-rich material, but if they’re dry, or you’re using corn cobs, they should be balanced with nitrogen-rich green matter.

The various options you have to compost your cobs, and other corn scraps include:

  • Hot compost
  • Cold compost
  • Vermiculture (worm compost)
  • Mulch

Hot Compost

Adding corn cobs to your hot compost heap or bin is one of the fastest ways to get them broken down and incorporated into your garden or potting soil. The bacteria that create heat will break down the moisture-rich parts of the cob, leaving the woody inner structure to be broken down later by fungi.

The smaller the pieces, the more quickly they will decompose. Since it can take up to 6 months for the cob material to be fully broken down, be sure to inspect the compost when you aerate and water it to stay aware of how the progress is going.

Cold Compost

In a cold compost, corn cobs will take much longer to break down. Since an open-air compost heap doesn’t hold as much heat as a bin or a tarp, there won’t be as high bacteria populations to break down the organic matter. Fresh cobs will have time to dry out, and the turnover may be up to a year long for them to fully be broken down.

Some gardeners recommend keeping corn cobs to certain, designated compost piles so that you can use some sooner than others that have corn cobs or dry corn stalks.

Vermiculture (Worm Compost)

Worm composting is another “fast” way of breaking down your corn cobs, but it will still take several months for the woody centers to be completely broken down. Worms will love the fibrous and nutrient-rich cobs, as well as any leafy material. Since the cobs don’t create an acidic environment, your worms will happily accept any corn scraps directed their way.


Mulching your corn husks is another great way to use your kitchen, garden, or field scraps. The large husks and leaves of corn stalks provide wide, high surface-areas materials that will slowly break down over the winter season and incorporate back into the soil.

The leaves may need to be mixed with other mulching material or applied during a moist time of year, so they don’t dry up too much or blow away.