Mold in compost is usual and shouldn’t be a worry. It’s pretty common to see moldy spots in your compost as the organic materials decompose in warm and humid conditions. But, it becomes worrying when excessive mold in your compost affects the composition and function of the microorganisms.
Our gardening team will tell you more about mold growth on compost and how it works to benefit your garden.
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What Reasons Cause Mold In Compost?
Mold in compost is caused by its natural decomposition process. It’s enhanced by the warm and humid conditions which break down the organic matter. If it’s appropriately mixed with your compost, seeing mold is nothing to worry about. However, too much mold is caused by the wrong conditions.
Black mold in compost bags is something you don’t want to see because it means that decomposition isn’t going well. It might indicate that there’s too much moisture or you didn’t provide adequate conditions to break down compost.
So, if you don’t see your compost breaking as it should, this might be caused by a problem with the conditions surrounding your pile.
– Improper Moisture
Having sufficient moisture is crucial for the decomposition of compost. The microorganisms in compost need high levels of moisture to thrive. In the right moist and humid conditions, bacteria can perform their primary function, breaking compost components. Moreover, bacteria use water to move around the pile.
Yet, if the compost is too dry because you keep it in a hot and dry spot, the bacteria will move slowly, slowing down the breakdown rate of compost. When the compost is too wet, the extra water will push the air out of the gaps in the compost, and the lack of air will affect how the microorganisms work to decompose compost.
With the lack of air, the bacteria will switch to anaerobic decomposition. This slows down the decomposition process and can lead to the formation of foul odors.
– Bad Aeration
Air is another crucial component of the decomposition process. The bacteria in compost need air to breathe.
Your pile might not have enough air if it has been sitting for too long. Choosing the wrong type of compost can also decrease the amount of air. This is more common when you choose finely textured compost that can quickly press, eliminating the air gaps in your pile.
The bacteria that break compost components can still function without air, but the breakdown process will be slowed down. You’ll notice more mold forming on your compost because it isn’t breaking down properly.
– Inadequate Temperature
The bacteria in compost need heat to break down their components. In cold temperatures, the bacteria would still be able to do their function, but the process would be slowed down significantly. As a result, you might see mold forming because the weather is too cold.
This happens when you store compost in a cold place or don’t keep it warm enough. The lack of heat will affect the nutrients released from the compost, so that it won’t be as healthy for your garden.
– Wrong Components
Compost should be made of balanced components to break down properly. It’s essential to have an equally balanced compost of green and brown components to decompose.
The green components provide the bacteria with essential nutrients, and the brown components provide them with air to break down the compost. When there are too many green components, the bacteria won’t be able to perform their functions well. With too many brown components, the compost will have too much air and insufficient nutrients.
Moreover, the decomposition process will be affected if inorganic components are mixed with organic compost. Inorganic components get into compost due to mistakes like bagging and shipping issues, but these components don’t add nutritional value to the soil.
How To Fix Mold In Compost
To fix mold in compost, as long as they’re properly mixed, you shouldn’t do anything. However, if you notice too much mold, you should adjust moisture, temperature, and air levels and make sure that your compost contains the right components.
– Adjust Moisture
Compost piles should have adequate moisture to be able to break down properly. You can test the moisture level in your compost by doing the squeeze level. Too much moisture in the compost will increase the level of mold. It’s healthy to have some mold, but it should be balanced and adequately mixed with the other components of your pile.
You should hold some of the compost in your hand and press it to make a ball. If the compost forms a ball and leaves a glistening residue, it has enough moisture. If it’s too wet, this compost won’t be able to break down properly, and you should add more dry components. This will restore adequate moisture levels to create a balanced compost.
If the compost breaks down into small pieces and doesn’t form a firm ball, then the compost is too dry. You should add some water or wet ingredients to the compost to adjust its moisture level.
– Fix Aeration
Detecting a foul smell indicates that your compost is undergoing anaerobic decomposition because of the lack of air. This doesn’t mean the components won’t break, but the breaking down process will be significantly slower, and your pile will show signs of stress and struggle.
So, how to get rid of mold in compost? First, you should ensure you add the right components to your compost. If the compost’s components are too finely textured, you can add some significant components like bark shreds and shredded leaves and mix them well.
Stalks, straws, and other coarse and thick materials are high in carbon content and will accelerate decomposition. This will create air pockets in your pile and improve the aeration in your compost. You should also rake and turn your compost regularly to improve aeration. This is especially crucial after hosing it down or keeping it outside in the rain.
If you notice that the compost smells bad because of lack of air, you can add sawdust or chimney ash to absorb the foul odor and then rake your compost. This will help eliminate the bad smell and allow bacteria to decompose and break down your compost.
– Adjust Temperature
Compost will break down in cold temperatures, but the decomposition process slows down significantly when the temperature drops.
Ideally, compost will break down with best results when the temperature is between 130 and 160 degrees Fahrenheit. And if the pile is built correctly, it will reach this temperature within 24 and 36 hours.
In these conditions, it’s pretty standard to see mold spores on the top of the decaying matter in your compost. This doesn’t mean that you’re doing anything wrong.
The only time your compost will completely stop breaking down is when the components are frozen. This rarely happens because the compost pile’s core will remain warm enough to support the decomposition process even when the temperature drops.
– Balance Components
An increase in the mold in your compost indicates that the carbon and nitrogen components aren’t balanced. This is why your compost should have enough green and brown matter to break down properly.
Ideally, you should maintain a carbon-to-nitrogen ratio of 30 to 1. So, you should provide 30 parts of dead leaves, wood chips, shredded paper, sawdust, and straw, which provide the pile with water-soluble organic carbon substances like fructose and cellulose.
Some homeowners and gardeners add inorganic fertilizers to their compost. These don’t affect the decomposition process, but you shouldn’t add too much.
So, can you add food scraps to your compost? Not all food remains should go into your pile. However, some of them can quickly and perfectly break down to release beneficial nutrients.
You can add several kitchen scraps to your compost, including paper, newspaper sheets, wax-coated baking sheets, crushed egg shells, tissues, corks, pet waste, and chicken and herbivore manure. But you should avoid plastic, styrofoam, dairy, meat, bones, and cooked food.
Conclusion
Noticing mold in compost is quite normal. However, paying attention to the mold type and its amount is essential.
- Seeing green or white mold is fine, but pink mold means that your compost pile contains some artificial cleaners and other chemicals.
- Adjusting moisture levels to accelerate and support the decomposition process is crucial.
- If your compost smells terrible, rake it or add brown components to improve aeration.
- Maintain an adequate carbon-rich and nitrogen-rich components ratio and keep your compost warm for successful decomposition.
With these tips, you can enjoy beneficial compost that adds nutrients to your soil. Moreover, you’ll be able to recycle many of the components you can find in your kitchen and garden.