9 Common Compost Problems & Easy Fixes

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Composting is a fantastic way to reduce waste and create nutrient-rich soil, but sometimes things don’t go as planned.

Smelly bins, pesky pests, moldy piles, or slow decomposition can all throw a wrench in your composting journey. 

Don’t worry — these issues are common, and most have simple fixes. In this guide, we’ll walk you through the most frequent composting problems and how to solve them so your compost stays healthy and productive.

Here is a list of the 9 most common compost issues & simple solutions:

1. Smelly compost bin 

A compost bin that smells bad isn’t normal – but what it smells like can help you figure out the problem. Different odors point to different imbalances in your pile. Here’s a quick guide:

Smell	Possible cause	Fix
Sewage / Rotten eggs	Anaerobic conditions — too wet, compacted, no airflow	Turn the pile, add dry browns (like cardboard or shredded paper), and improve ventilation
Vinegar / Sour	Too much acidic food waste (like citrus), or an overly green-heavy pile	Balance with more browns; avoid adding too much acidic material
Ammonia	Too much nitrogen (greens like food scraps, grass clippings)	Turn the pile, add browns, improve drainage
Rotten / Putrid	Rotting food from lack of oxygen or excessive moisture	Turn the pile, add browns, improve drainage
Petrol / Chemical	Possible contamination (non-compostable plastics, treated wood, or chemicals)	Remove synthetic materials; only add certified compostable items
Sweet / Alcohol-like	Fermentation, often in sealed bins or Bokashi setups	It’s okay in Bokashi; if not, open it up and mix it with browns to reduce it

Most common with:

• Worm bins: Can smell if overfed, too wet, or scraps not buried.
• Bokashi bins: Naturally smell vinegary due to fermentation (normal), but can go bad if not drained.
• Indoor countertop bins: Prone to smells if not emptied regularly or filtered properly.
• Cold piles: Especially if not turned or layered properly.

2. Compost is slimy or soggy

Cause: Too many wet food scraps or poor drainage, plus not enough dry materials to absorb moisture.

Fix: Add lots of dry browns (paper, straw, cardboard) and turn the compost regularly to improve airflow and help it dry out. If your bin doesn’t drain well, consider drilling some holes or raising it off the ground a bit.

Most common with:

• Bokashi bins – The fermentation process produces liquid, which sometimes can cause soggyness.
• Countertop bins or sealed containers – Limited airflow causes moisture buildup.
• Tumblers – If overloaded with greens or not turned enough.

3. Compost is too dry

Cause: Too many dry browns and not enough moisture or nitrogen-rich greens. Dry, hot weather, or windy conditions can also dry out your pile.

Fix: Add water slowly while mixing, and toss in some green scraps like fruit and veggie peelings to bring moisture and nitrogen back.

Most common with:

• Tumbler composting – Tumblers are often exposed to wind/sun, and moisture evaporates.
• Outdoor cold piles – Especially in dry climates or summer.
• Rare in worm or Bokashi systems, as they’re usually sealed and retain moisture.

💡 Moisture tip: The ideal moisture level feels like a damp sponge — moist but not dripping. This balance helps microbes thrive and speeds decomposition.

4. Compost isn’t breaking down / decomposition is slow

Cause: Unbalanced mix of materials (too many browns or greens), poor airflow, or cold weather slowing things down.

Fix: Chop up large scraps into smaller pieces to speed breakdown. Balance greens and browns (roughly 1:2 by volume), and turn regularly to add oxygen. In winter, insulate your pile or switch to cold composting.

Tip: Adding a handful of finished compost or a compost starter can jumpstart the process.

Most common with:

• Tumbler composting – If not turned regularly.
• Cold pile methods – Especially during winter.
• Worm bins – If overfed or bedding is wrong (e.g., too acidic).

5. Pests like rats, raccoons, or mice invading

Cause: Meat, dairy, oily foods, or uncovered food scraps attract unwanted visitors.

Fix: Avoid composting animal products. Use a sealed bin with a secure lid, and always bury food scraps under a layer of brown.

Note: For pest-prone areas, raised bins or enclosed tumblers work best.

Most common with: Outdoor cold piles, or open compost heaps

6. Fruit flies or gnats buzzing around

Cause: Exposed fruit scraps and overly moist indoor bins create a fly haven.

Fix: Always cover fresh scraps with a layer of dry browns. Keep your countertop bin sealed and empty it regularly.

Tip: Regularly empty and clean bins or freeze fruit scraps before composting.

Most common with:

• Worm bins – Especially if food isn’t buried properly.
• Countertop bins
• Bokashi bins – During warmer weather.

7. White bugs (springtails) or fuzzy mold appearing

Cause: These tiny critters and molds are usually signs of healthy decomposition, especially in moist conditions. However, too much moisture may increase growth.

Fix: Usually no action is needed — they help break down organic matter! If you see too much mold or bug activity, add more dry browns and turn the pile to balance moisture and airflow.

Note: White, thread-like mold (actinomycetes) smells like fresh soil and is a good sign!

8. Compost pile too hot (steaming or overheating)

Cause: Too many nitrogen-rich greens in a big pile can cause high temperatures.

Fix: Mix in more browns and turn your pile to regulate the heat.

Note: A warm pile (up to 160°F/71°C) means your microbes are hard at work — it’s a good thing! Just watch it doesn’t dry out or burn.

Most common with: Hot aerobic composting or large outdoor piles

9. Compost pile too cold and inactive

Cause: Cold weather, too small a pile, or not enough greens or turning can make decomposition slow.

Fix: Insulate your pile with straw or a tarp, increase the pile size, add more green scraps, and turn regularly.

Tip: Composting slows down in winter but will pick up again when it warms.

Most common with: Outdoor cold piles

When NOT to worry  

Not sure if your compost is on track? Here are clear signs things are going right — and that your pile is healthy, active, and doing what it should. Here is a list of signs to look for:

• It feels warm in the middle – microbial activity is breaking down your scraps (a good hot pile can reach 130–160°F / 54–71°C).
• There’s a rich, earthy smell – not sour, rotten, or ammonia-like.
• You see steam when turning it (especially outdoors in cool weather).
• Materials are visibly breaking down within weeks (if hot composting).
• You see small bugs, worms, or decomposers – a living ecosystem!
• Moisture is balanced – like a wrung-out sponge: not too soggy, not too dry.

When to start over

Sometimes compost gets too out of balance and can’t be saved easily. If your pile smells terrible despite fixes or is filled with pests, it may be time to start fresh.

You can use your current compost as a soil amendment for non-edible plants and begin a new batch with better balance.

FAQs

What are “browns” and “greens” in composting?
Browns are carbon-rich materials like dry leaves, shredded paper, straw, and cardboard. Greens are nitrogen-rich items such as fruit and vegetable scraps, coffee grounds, and fresh grass clippings. A good compost balance usually means about 2 parts browns to 1 part greens. Learn all about this & other key terms here.

What do white bugs or fuzzy mold mean in my compost?
Small white bugs (springtails) and white mold are normal and usually signs of healthy decomposition. They help break down organic material.

How do I know if my compost is too wet or too dry?
Compost should feel like a wrung-out sponge — damp but not soggy or muddy. If it’s dripping water or smells bad, it’s too wet. If it’s dry and crumbly, add water and green scraps.

What is the ideal temperature for composting?
Active compost piles often reach 130-160°F (54-71°C). Warmth means microbes are breaking down materials effectively. If it’s too cold, decomposition slows.

How often should I turn my compost?
Ideally every 1-2 weeks for fast decomposition. Turning adds oxygen, which helps microbes break down material and prevents bad smells.

Final thoughts

Troubleshooting compost problems is all about paying attention and adjusting your mix of greens and browns, moisture, and airflow. 

Keep turning your compost, balance your ingredients, and make sure your bin is secure and well-ventilated. 

Happy composting!