So you've picked a composting method that works for your space and lifestyle (if you're still deciding, check out our previous post on choosing the right method). Now comes the fun part—actually turning your kitchen scraps and yard waste into garden gold! But what happens when things don't quite go according to plan? I've had my share of composting mishaps over the years, and I've learned that understanding the basic factors that influence composting can help solve the most common problems.

In this post, I'll share the four essential factors that influence composting success and provide practical solutions to the most common composting challenges. Whether you're a beginner facing your first compost setback or an experienced composter looking to optimise your process, you'll find actionable advice to keep your compost healthy and productive.

The Four Key Factors That Make or Break Your Compost

Whether you're composting in a pile, bin, or worm farm, four interconnected factors determine how efficiently organic matter breaks down. Understanding these elements helps keep your compost healthy, odour-free, and actively decomposing.

1. Temperature: The Heat Engine of Decomposition

Compost microbes thrive in warm conditions. In hot composting, temperatures should ideally reach between 50–60°C (122–140°F), which accelerates breakdown and kills pathogens and weed seeds. Even in cold composting, maintaining some warmth speeds up the process.

If your pile isn't heating up:

• It may be too small (aim for at least a 3×3×3 foot pile for hot composting)
• It could be too dry (see moisture below)
• You might need more nitrogen—try adding "greens" like grass clippings, coffee grounds, or vegetable scraps
• The pile might need turning to reactivate decomposition

If your pile is overheating (rare in home composting, but possible in summer):

• Temperatures above 65°C (149°F) can actually slow decomposition by killing beneficial microbes
• Turn the pile to release excess heat and introduce more oxygen
• Consider adding more browns if the pile seems too dense

Seasonal considerations:

• In winter, insulate your pile with a thick layer of straw or leaves to maintain heat
• In summer, provide some shade if the pile seems to be drying out too quickly
• Insulated bins help maintain consistent temperatures year-round

2. Moisture: The Goldilocks Zone of Dampness

Microbes need water to digest organic material, but too much or too little halts the process. The goal is to maintain the "wrung sponge" level of moisture—when squeezed, a handful of compost should feel damp but only release a drop or two of water.

If your compost is too dry:

• Materials remain unchanged for weeks
• The pile feels dry and dusty
• You might see ants taking up residence (they prefer dry conditions)

Solution: Water the pile while turning it, and add some fresh greens or even a scoop of finished compost to reintroduce microbes. After moistening, activity should resume as long as the temperature is adequate.

If your compost is too wet:

• You'll notice a soggy, matted texture
• It might have a rotten egg or sewage smell (anaerobic conditions)
• You'll see a slimy layer, often from food scraps breaking down anaerobically

Solution: Add plenty of dry browns (shredded cardboard, dry leaves, wood chips) and mix them in thoroughly. These materials will absorb excess moisture while creating air pockets. Turn the pile thoroughly to incorporate oxygen.

Pro Tip: In rainy seasons, consider covering your pile with a tarp that allows airflow but prevents saturation. In dry weather, collecting shower water while it warms up is an eco-friendly way to moisten your compost.

3. Aeration: Keeping Your Compost Breathing

Composting is an aerobic process—the beneficial microbes need oxygen. Without sufficient air, anaerobic microbes take over, producing foul odors and slowing decomposition.

Signs of poor aeration:

• Foul, sulfurous or sewage-like odors
• Slimy, matted texture
• Very slow decomposition
• Visible mold growth

Solutions for better aeration:

• Turn or mix the compost always helps (this will depend on your comfortable level for the turning frequency)
• Include coarse materials like small twigs, stalks, or shredded cardboard to create air pockets
• For enclosed bins, ensure ventilation holes aren't blocked
• If using a tumbler, rotate it several times weekly (give it a turn every time you feed the composter)

Pro Tip: A good mix of particle sizes creates natural air channels. Aim for approximately 60% fine materials and 40% coarser materials to maintain good airflow while providing sufficient surface area for microbes.

4. Particle Size: The Forgotten Factor

Smaller pieces of material break down much faster because microbes can only work on surfaces. Increasing the surface area by reducing particle size dramatically accelerates decomposition.

Optimal particle sizes:

• Food scraps: Cut into 1-2 inch pieces
• Branches and twigs: Break or cut into 2-5 inch pieces
• Leaves: Shred if possible, especially waxy ones like magnolia or oak
• Paper and cardboard: Tear or shred into strips
• Eggshells: Crush to speed decomposition

Caution: While smaller is generally better, extremely fine materials (like sawdust) can compact and restrict airflow. If adding very fine materials, mix them thoroughly with coarser items.

Pro Tip: Keep garden scissors or a small pruner near your kitchen compost collector to quickly cut larger scraps before adding them to your compost. If you have a garden shredding machine, all the garden waste and cardboard can run through the machine before adding into your compost bin.

Common Composting Problems and Their Solutions

Actually, many of these problems I've covered in my previous posts whenever the related information is shared. Here I gather them up as Problems-Solutions for faster reference.

Problem: Foul Odours (Rotten Egg or Sewage Smell)

Cause: Anaerobic decomposition due to too much moisture, compaction, or excess greens.

Solution:

1. Turn the pile immediately to introduce oxygen
2. Add dry, carbon-rich browns (shredded cardboard, dry leaves, straw)
3. Ensure proper drainage if the bin is waterlogged
4. Check that ventilation holes aren't blocked

Prevention: Maintain a good balance of browns to greens (aim for that 2-3:1 ratio by volume), and always cover fresh food scraps with brown materials.

Problem: Ammonia Smell

Cause: Too much nitrogen (excess greens) causing ammonia gas release.

Solution:

1. Add more carbon-rich brown materials immediately
2. Turn the pile thoroughly to incorporate the new materials

Prevention: Keep a stockpile of browns (leaves, cardboard, paper) ready to add whenever you include kitchen scraps or other nitrogen-rich materials.

Problem: Pile is Not Breaking Down/Decomposing Very Slowly

Cause: Could be several factors—too dry, too much carbon, too cold, or pieces too large.

Solution:

1. Check moisture level and add water if the pile is dry
2. Add nitrogen-rich materials like coffee grounds, fresh grass clippings, or even a small amount of organic fertiliser as a "nitrogen boost"
3. Turn the pile to activate decomposition
4. Cut materials into smaller pieces
5. Ensure the pile is large enough to generate and retain heat (for hot composting)

Prevention: Maintain proper moisture, turn regularly, and chop materials before adding them to the pile.

Problem: Attracting Pests (Rodents, Flies, etc.)

Cause: Exposed food waste, especially meat, dairy, or oily foods.

Solution:

1. Bury food scraps in the center of the pile, at least 8-12 inches deep
2. Add a thick layer of browns on top of any food additions
3. Consider using a rodent-resistant bin with a secure lid and fine mesh bottom
4. For fly problems, stop adding fruit and vegetable scraps temporarily and cover the pile with a thick layer of browns or soil

Prevention:

• Always bury food scraps rather than placing them on top
• For pest-prone areas, avoid composting meat, dairy, and oily foods in open piles
• Use enclosed bins with tight-fitting lids or hot composting bin in urban areas

Problem: Compost Too Wet and Soggy

Cause: Too much moisture from rain, too many wet green materials, or poor drainage.

Solution:

1. Add dry browns like shredded cardboard, newspaper, or dry leaves
2. Turn the pile thoroughly to distribute moisture
3. Cover the pile during heavy rain
4. Ensure the bin or pile has adequate drainage

Prevention: Monitor the weather and cover the pile before heavy rain. Maintain a good balance of wet and dry ingredients.

Problem: Compost Too Dry

Cause: Not enough moisture, too much sun exposure, or too many dry brown materials.

Solution:

1. Add water gradually while turning the pile
2. Incorporate more green (high-moisture) materials
3. Cover the pile to retain moisture

Prevention: Check moisture levels regularly, especially during hot weather, and water as needed.

Problem: Weed Seeds in Finished Compost

Cause: Pile didn't reach high enough temperatures to kill seeds, or weeds were added after the hot phase.

Solution:

1. If the weed seeds bother you, consider using a hot composting method.
2. Use the compost for established plants rather than seedbeds

Prevention:

• Maintain hot composting temperatures (above 55°C/131°F) for at least 3 days

Problem: Spring/Autumn Scarified Moss Grass Difficult to Compost

Cause: Moss can be a nightmare for home composters, even experienced ones. While moss does contain moisture, it's very difficult to break down. Lawn scarifying activities create abundant quantities of moss, and if you simply throw it into your compost, it becomes a compacted dry layer that won't break down at all.

Solution: After scarifying your lawn, collect the moss in piles and use your mower to shred it further. When adding moss to your compost, treat it as a "brown" material rather than green. Mix it thoroughly with green materials, then add water to increase moisture. Compost containing moss tends to dry out quickly and compacts easily, so occasional turning and adding more moisture when needed will definitely help.

A moss and dry grass mixture can be an excellent brown material during summer when other browns might be scarce. I haven't mentioned pH values much in this post because home composting rarely has serious pH issues. However, moss can make compost more acidic during decomposition, though the pH will eventually neutralise as the compost matures.

Specialised Troubleshooting for Different Composting Methods

If you're using one of the alternative composting methods we discussed in our previous post, here are some specific troubleshooting tips:

For Vermicomposting (Worm Bins)

Problem: Worms are dying or trying to escape

• Cause: Bin conditions have become unsuitable—too wet, too dry, too acidic, or too hot/cold.
• Solution: Check moisture (should be like a wrung-out sponge), ensure temperature is between 15-25°C (59-77°F), and add fresh bedding. If bin smells acidic, add crushed eggshells or a small amount of garden lime.

Problem: Fruit flies

• Cause: Exposed food scraps.
• Solution: Bury food under 2-3 inches of bedding and stop adding food for 1-2 weeks to break the fly lifecycle. Add a thick layer of dry bedding on top.

For Bokashi Systems

Problem: Mold that's not white

• Cause: Contamination or poor sealing.
• Solution: White mold is normal and good; blue, green, or black mold indicates problems. Remove the affected layer, add more Bokashi bran, and ensure the bucket is sealed tightly.

Problem: Extremely foul smell (not pickled/fermented smell)

• Cause: Putrefaction instead of fermentation.
• Solution: If the smell is putrid rather than pickled/sour, the batch may be failing. Add more bran, ensure tight sealing, and drain liquid more frequently.

For Insulated Bin Composters

Problem: Not maintaining temperature

• Cause: Insufficient feeding, poor balance, or extremely cold weather.
• Solution: Add more material (especially nitrogen-rich) weekly, ensure proper moisture, and check that vents are adjusted correctly for the season.

For Electric Composters

Problem: Still wet after cycle

• Cause: Overfilling or adding too many wet materials.
• Solution: Reduce batch size, mix in drier materials, or run a second cycle.

Problem: Strong odors during processing

• Cause: Certain foods like onions or fish can create strong smells.
• Solution: Clean the filters more frequently and consider avoiding particularly odorous foods.

Composting Through the Seasons

Composting is a year-round activity that shifts with the changing seasons. Each time of year brings its own challenges and opportunities for home composters.

Spring: Awakening Your Compost

Spring is a time of renewal for your compost pile after the winter slowdown. As temperatures gradually rise, microbial activity in your pile will begin to increase. This is the perfect time to give your winter-dormant pile a good turn to reintroduce oxygen and assess moisture levels. I've found that spring piles often need moisture adjustments after winter—sometimes too wet from our notorious wet weather, other times too dry from being covered.

The emerging greenery in your garden also provides an opportunity to start balancing your compost materials. While you'll have more green materials becoming available, this is also when I start consciously collecting and storing browns for the upcoming seasons. Having a stash of dried leaves or cardboard ready will serve you well when summer's abundance arrives.

Summer: Managing Heat and Abundance

Summer brings both challenges and opportunities to composting. The warm weather accelerates decomposition, but also increases moisture evaporation. During hot summer months, I check my compost's moisture levels more frequently, sometimes adding water during dry spells. If your pile sits in direct sunlight, providing some shade can help prevent excessive drying.

Summer gardens typically generate abundant material—from grass clippings to vegetable garden trimmings. This green material influx is perfect for rapid composting, but remember to balance it with sufficient browns to prevent soggy, smelly conditions. I find summer is when my compost is most active, sometimes completing a cycle in just 6-8 weeks with proper management.

Autumn: Harvesting Nature's Bounty

Autumn is perhaps the most crucial season for composters, as it provides an opportunity to stock up on carbon-rich brown materials for the entire year. Fallen leaves are composting gold! I collect far more than I need immediately, storing extras in bags or bins for use throughout the winter and spring when browns can be scarce.

During fall cleanup, consider shredding leaves before adding them to your pile—they'll break down much faster. With the abundance of material, autumn is also an ideal time to start new piles or fill dormant bins. For extreme leaf abundance, a separate leaf mold pile can be valuable—simply pile up leaves, keep them moist, and in 1-2 years you'll have wonderful leaf mold for garden use.

Winter: Maintaining Activity During Dormancy

Winter composting varies dramatically depending on your climate. In colder regions, decomposition slows significantly or even pauses during freezes, but that doesn't mean your composting efforts should stop. I continue adding kitchen scraps throughout winter, even when the pile is dormant.

The larger your winter pile, the better it will maintain internal warmth. Don't worry if your pile freezes—it will simply resume activity in spring, and the freeze-thaw cycles actually help break down materials physically by splitting cell walls. Alternatively, you can also use hot composting bins, this type of bins still works in the winter time.

My Composting Philosophy

I've come to think of composting as less about getting everything perfectly right and more about collaborating with nature. When problems arise in my compost pile, I try to see them as feedback rather than failures. Each challenge has taught me something valuable about my specific composting ecosystem.

Most composting issues can be solved by adjusting one or more of the four key factors: temperature, moisture, aeration, and particle size. Keep these in balance, and your compost will thrive.

As mentioned several times in my post, you cannot fail in composting. Any compost that is not as perfect as store-bought compost, can still be used to mulch your garden plants. In any case, if you really are not sure whether it will cause problems to your plants, simply mix your compost with store-bought compost - dilution always works.

Next Steps in Your Composting Journey

Now that you understand how to maintain optimal composting conditions and troubleshoot common problems, you're well-equipped for success. In our next post, we'll explore "Compostable Products: What Actually Breaks Down (And What Doesn't)" to help you make informed choices about what goes into your compost bin.

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Perhaps you have even better ideas or solutions for the problems discussed in this post. Please share with us in the comments. It's always wonderful to learn from each other and the community can grow together.