🧪 Why C:N Matters in Vermicomposting

Worms thrive in a cool, stable, carbon-rich environment. They do not want heat spikes, strong ammonia, or rapid, hot decomposition.

Every material you add has some mix of carbon (C) and nitrogen (N). VermiCalc helps you balance them.

Ideal Vermicompost C:N Range

• Target range: ~42:1
• Higher carbon supports a gentle, worm-friendly environment.
• Too much nitrogen increases the risk of odors and worm stress.

Signs of Imbalance

• C:N too high (too much carbon): bin feels dry, food sits for a long time, worms cluster where food is softest.
• C:N too low (too much nitrogen): strong smells, wet or slimy patches, worms trying to escape or hiding at the edges.

VermiCalc lets you see the ratio before you build or adjust a bin, so you can make small, smart changes instead of big rescue operations later.

🍂 Carbon (“Browns”) — Bedding Materials

Carbon-rich materials form the bedding in a worm bin. They create structure, hold moisture, and give microbes and worms a safe home.

Common Bedding Materials

• Shredded cardboard and egg cartons
• Shredded paper (non-glossy, black-and-white)
• Coco coir
• Shredded brown paper bags
• Dry leaves
• Coffee filters and paper tea bags
• Aged sawdust or wood shavings (in small amounts)

Why Carbon Matters

• Prevents sour or rotten odors
• Absorbs excess moisture and nitrogen
• Improves airflow and prevents compacted, slimy areas
• Buffers acidity and keeps worms comfortable

A simple rule for most worm bins: Use 2–3 times more bedding (browns) than food (greens) by volume.

🥬 Nitrogen (“Greens”) — Worm Food

Nitrogen-rich materials are the food worms and microbes break down. The goal in vermicomposting is slow, steady processing — not heat.

Worm-Friendly Foods (Greens)

• Fruit and vegetable scraps
• Melon rinds and pumpkin
• Banana peels
• Coffee grounds (in moderation)
• Cooked rice or pasta (small amounts)
• Used tea leaves
• Soft plant trimmings

Use with Caution or Avoid

• Meat, dairy, oily or greasy foods
• Very salty or heavily seasoned leftovers
• Large amounts of citrus, onions, or garlic
• Spicy peppers and hot sauces
• Large amounts of bread or baked goods (can ferment quickly)

Chop food into smaller pieces, bury it under bedding, and stop feeding if you notice odors or uneaten food building up.

⚖️ Adjusting Your Mix

Use VermiCalc to see where your mix lands, then make small changes until the C:N ratio is in a comfortable range for worms (around 42:1).

If the C:N is Too High (Too Much Carbon)

Bin will be slow, dry, and cool.

• Add small amounts of soft, worm-safe food (greens).
• Lightly mist with water if bedding feels dry or papery.
• Avoid huge feeding spikes; adjust gradually.

If the C:N is Too Low (Too Much Nitrogen)

Bin may smell, feel wet, or stress worms.

• Add plenty of dry bedding (cardboard, coir, shredded paper).
• Gently fluff the top layer to restore airflow.
• Pause feeding for a few days until things normalize.

General Worm Bin Tuning

• Keep bedding as moist as a wrung-out sponge.
• Maintain a thick top layer of dry bedding as a “blanket.”
• Add crushed eggshells or minerals to help buffer acidity.

⚠️ Common Worm Bin Issues

Worms Trying to Escape

Possible causes: acidity, ammonia, overfeeding, or anaerobic spots.

Fix: add dry bedding, stop feeding for a few days, and gently mix the top layer. Add crushed eggshells or a small amount of garden lime if the bin seems sour.

Bad Odors (Rotten, Sour, or Ammonia)

Possible causes: too many greens, poor airflow, compacted material.

Fix: add several handfuls of dry bedding, fluff lightly, and pause feeding until the smell fades.

Too Wet or Sloppy

Fix: mix in plenty of shredded cardboard, coir, or paper. Keep a dry bedding layer on top to absorb moisture.

Too Dry

Fix: lightly mist with water and add a small amount of moist food. Do not drench the bin; aim for even moisture.

Protein Poisoning (Deadly for Worms)

Symptoms: Worms resemble a string of pearls, mass die-off in pockets.

Fix: immediately add a large amount of fresh bedding, stop feeding, and allow the bin to rebalance before feeding again.

Mites, Gnats, and Other Small Critters

Many tiny creatures are normal in worm bins, but large outbreaks usually mean extra moisture or food.

• Add dry bedding and reduce feeding.
• Use a dry top layer of paper or cardboard.
• For gnats, consider using Bti (mosquito dunks) in the area around the bin.

A healthy vermicompost system smells earthy, runs cool, and has worms spread throughout the bedding, not just escaping at the lid.