Composting is an amazing way to recycle food waste and garden trimmings into a nutrient-rich fertilizer for your garden. However, a common problem many composters face is foul odors coming from the compost pile.
While a little earthy aroma is normal, a strong rotten or ammonia-like smell indicates something is off with your compost. Don’t let a smelly compost bin discourage you from this eco-friendly practice! With a few troubleshooting tips, you can Stop Compost From Smelling.
In this comprehensive guide, we’ll explore the top reasons for compost odor and actionable solutions to stop the stink permanently. Get ready to breathe easy while making “black gold” for your garden. Let’s get started!
Why Does Compost Smell Bad?
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Before jumping into fixes, it helps to understand what causes compost odor in the first place. Here are the most common culprits of compost stench:
Excess Moisture
Too much moisture robs oxygen from the compost pile, creating an anaerobic environment. This prohibits aerobic bacteria from breaking down the waste efficiently. As anaerobic bacteria take over, they produce foul-smelling hydrogen sulfide gas — think rotten eggs!
Unbalanced Carbon & Nitrogen Ratio
Microbes need both carbon (browns) and nitrogen (greens) to thrive. Too many nitrogen-rich greens, like food scraps and grass, can cause an ammonia smell. On the flip side, too many carbon-rich browns, like leaves and paper, leads to a musty, woodsy odor.
Compaction
Lack of air flow is another route to anaerobic conditions. Dense materials like sawdust, leaves, and hay can compact and prevent oxygen from circulating. Turning and fluffing the pile is key!
Cold Weather
In colder temperatures, microbial activity naturally slows down. This lag time allows odors to build up. Insulating the compost pile can help maintain warmth and airflow.
Wrong Materials
Certain items like meat, oils, and dairy don’t break down quickly. They also emit a potent, rotting stench. Keep composables plant-based for the best results.
Now that we know why compost can smell, let’s go over proven techniques to stop the stink and get your pile back on track!
6 Ways To Stop Compost From Smelling
1. Add More Browns
If you suspect excess nitrogen is the issue, incorporate more carbon-rich browns like dried leaves, shredded newspaper, sawdust, straw, or cardboard. Aim for a 25-30:1 carbon to nitrogen ratio. The browns balance the nitrogen and soak up extra moisture.
2. Turn & Fluff the Pile
Turning or stirring the compost pile introduces much-needed air. Use a pitchfork or compost aerator to lift and flip materials. Break apart any clumps as you go. Turning weekly is ideal, even more often if odor persists.
3. Add a Cover
A simple tarp goes a long way to protect the compost from excessive rain. Waterlogged conditions severely hinder airflow. You can also use a lid designed for compost bins. Just be sure the cover still allows for ventilation.
4. Insulate the Pile
In cold weather, insulate the pile to retain heat for active composting. Layer the pile with straw or cover with an insulated compost blanket. The ambient warmth encourages microbial activity to prevent odor buildup.
5. Bury Food Deeply
Rather than leaving food scraps exposed on top, dig holes at least 12 inches deep to bury compostables. Keeping scraps contained prevents flies, pests, and associated odors.
6. Maintain Proper Moisture
The compost pile should have the moisture content of a wrung-out sponge. If compost is soggy, add more browns to soak up excess moisture and promote airflow. You may need to turn the pile more frequently until an optimal moisture balance is achieved. Monitoring with a compost moisture meter takes the guesswork out!
3 Tips To Prevent Compost Odor
Once you troubleshoot and fix any existing smells, it’s equally important to take preventative measures moving forward. Here are smart tips to keep your compost smelling fresh:
- Shred Materials – Breaking down large pieces exposes more surface area for composting microbes to work. This speeds decomposition so odors have less time to develop. Use a chipper-shredder, lawnmower, or shear for easy shredding.
- Aerate Often – Don’t just turn the pile when it smells. Get in the habit of aerating with a pitchfork or compost turner once a week or so. Regular mixing redistributes moisture and prevents densely packed sections.
- Blend Greens & Browns – Each time you add scraps to the pile, ensure you’re blending complementary greens and browns. Diverse compositions keep microbe populations happy and compost smells at bay.
Common Compost Odors & What They Mean
Sometimes a whiff of the compost pile can provide clues about underlying issues before they escalate. Here’s a breakdown of common compost smells and what they indicate:
Earthy, forest floor scent – This mild, pleasant aroma is normal and means your compost is healthy and breaking down!
Rotten eggs – The stench of hydrogen sulfide gas signals anaerobic conditions due to excess moisture, compaction, or lack of aeration. Time to turn the pile!
Vinegar, wine, or sour smell – Acetic acid is produced when there’s too much green waste in the mix. Add more carbon-rich browns.
Ammonia or urine odor – Too much nitrogen from food, grass clippings, or manure leads to excess ammonia gas. Dilute with carbon materials.
Musty, moldy, or woodsy smell – An overload of woody browns can create this aroma. Balance with nitrogenous greens.
Rotten meat or rancid smell – Meat, oils, and dairy quickly putrefy and stink. Exclude these items from your compost. Bury any you add very deeply.
When in doubt, refer to this smell chart to diagnose the issue. Then take prompt action to remedy compost smells before they get out of hand.
Troubleshooting Specific Compost Odors
Let’s go over how to tackle two of the worst compost offenders – rotten egg and ammonia smells. Resolving these will make the biggest impact on odor issues.
Fixing Rotten Egg Scent
As we touched on earlier, rotten egg odor screams excess moisture and anaerobic conditions. Here are 5 fixes to dissipate the stench:
- Turn the pile to reintroduce oxygen
- Add dry browns like leaves, straw, or sawdust to absorb moisture
- Create airflow with sticks or pipes poked into the pile
- Cover with a tarp to protect from rain
- Spread out compost to dry if overly saturated
Turning is the first line of defense. But you’ll also need to address the wetness factor to prevent the smell from returning quickly.
Stopping Ammonia Smell
Too much green waste emits an ammonia odor as nitrogen breaks down. Restore balance by:
- Mixing in carbon-rich browns like dried leaves, shredded paper, sawdust, or cardboard
- Avoid overloading with greens like fresh grass clippings or food waste
- Turn the pile to release excess ammonia gas
- Establish a 25-30:1 carbon to nitrogen ratio
Retaining this target carbon-nitrogen balance is the number one way to curb an ammonia stench long-term. Keep browns and greens in harmony!
Using Finished Compost With Odor
Mature compost ready for the garden should have an earthy, soil-like scent. But immature compost may still have some odor. Here are tips for handling:
- Allow unfinished compost to cure further if smells persist. Turn weekly to speed along the curing process.
- Screen out chunky debris and return uncomposted bits to the pile.
- Apply smelly compost underneath mulch where odors can off-gas before planting.
- Till compost with odor into the soil to dilute and contain smells.
- Limit use around plants until additional curing eliminates odor.
Don’t rush to use freshly made compost if odors seem strong. Let it mellow and stabilize a bit longer first.
When To Seek Professional Help
Our compost odor solutions will set most DIY piles straight. But if you’ve diligently tried the tips here without success, don’t lose hope. Sometimes it helps to bring in a composting pro for an assessment.
Signs it may be time for an expert opinion include:
- Foul odors persist after troubleshooting efforts
- The inside of the pile is sludge-like or soggy
- Evidence of pests like flies or rodents
- No signs of decomposition
- Failure of materials to heat up as expected
A seasoned composting pro can pinpoint issues in your unique pile and climate. They can test oxygen levels, moisture content, and pH to hone in on what’s amiss. Often a few personalized adjustments will get your compost back thriving.
Don’t Let Smells Deter Your Composting Journey
Now you’re equipped with expert advice to stop compost smells in their tracks. A few simple adjustments like adding browns, turning the pile, and monitoring moisture can nip odor issues before they become a big stink. Stay the course with your composting efforts. Keep these tips handy, and you’ll be creating sweet-smelling “black gold” to nourish your garden in no time!
