10 Reasons Your Compost Is Forming Balls (& How To Fix It)

compost balls
In most cases, clumping is a sign that your compost is too wet and is forming balls as a result. In compost tumblers, where clumping is encouraged by the rotating motion, compost balls are common.

Read on to see why these clumps are forming.

What does it mean if your compost forms balls?

The clumping of compost occurs when composting materials, which are prone to sticking together, are rolled around in a compost tumbler.

Most people begin by loading their kitchen waste into either a compost bin or compost tumbler and watch it slowly fill up. As time passes, they notice that everything in the bin or tumbler has consolidated into clumps.

The clumping of compost is primarily caused by compaction through settling. The material that you add to your compost bin will likely be wet or at least moist. 

This is especially true if your compost is to be primarily composed of kitchen waste. Clumps will form if there is a buildup of one type of kitchen waste and nothing else to keep it open. 

Wet and heavy waste will inevitably clump together. As more wet and heavy material is continuously loaded on top of it, it will sit there. By becoming sealed within themselves, the lumpy clumps are prevented from becoming compost.

Are compost balls bad?

Compost balls (golf ball sized and larger) are fine to use as they are. However, if you want a finer texture to your compost, then you may break the clusters up. 

Just because you have compost balls in your pile does not mean your compost is not nutrient-rich or useable.

Compost balls are great for:

  • Use under plants. Great for potting. As the balls release their nutrients more slowly, the plants will last longer.
  • Use as a rough mulch around fruit trees and shrubs. Mulch retains water, prevents weeds from growing, and reduces soil erosion.
  • Compost tea. You can increase the nutritional value of your compost by making compost tea.

The following compost ingredients cause compost piles to clump:

  1. The eggshells and citrus rinds that have only been broken in half. Anything with a hollow inside will fill up with compost and cause clumps.
  2. Grass clippings
  3. Eggshell cartons
  4. Cardboard and wet shredded paper
  5. Yard waste
  6. Too much brown material
  7. Too much green material
  8. Incorrect moisture level
  9. Not enough organic matter
  10. Incorrect balance of food scraps or food waste or kitchen scraps

How to fix compost clumping

If you just added a load of kitchen waste to the compost bin, add some shredded newspaper or ripped-up cardboard before adding more. 

By doing this, you will be able to prevent clumping of the compost you are making. The kitchen waste material will be able to breathe as a result.

How to prevent clumping compost

Clumping can be prevented by adding more ‘brown’ material to the compost.

Another common solution to the clumping problem is adding worms to the mix. In many compost bins, worms will find their way in without any effort from the owner.

Put some worms into your compost if there are none already present. Upon taking residence, they will work on all material that has not yet formed a clump. 

They gradually break down the entire clump by eating the material outside the clump.

Eventually, the worms will work their way into the clump and help turn it into compost.


Discovering composting as a way of life or even better, as nature’s way of recycling, Ana dedicates her time to trying out new methods of composting at home. Her goal is to share everything that she’s learned in the hopes that it will help others discover the amazing rewards of composting.

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