If you have started a wormery, one of the most important questions you will ask is simple:
What should I feed compost worms?
Get it right and your worms will thrive, multiply and produce rich compost quickly. Get it wrong and you may end up with smells, fruit flies or unhappy worms.
This UK guide explains exactly what to feed compost worms – and what to avoid.
What Compost Worms Love to Eat
Compost worms thrive on everyday kitchen waste. They prefer soft, moist organic material that breaks down easily.
Here is what to feed compost worms for best results:
- Fruit and vegetable peelings: Carrot tops, potato peelings, salad leaves and apple cores are ideal.
- Coffee grounds and tea leaves: Including paper tea bags – remove plastic-based bags first.
- Crushed eggshells: Rinse and crush them to help balance acidity.
- Shredded paper and cardboard: Plain, uncoated paper adds bedding and balances moisture.
- Soft garden waste: Dead leaves and small plant trimmings in moderation.
In the UK, most household food waste fits neatly into these categories. Chop larger scraps into smaller pieces to speed up decomposition and make it easier for compost worms to process.
How Much Should You Feed Compost Worms?
Compost worms can eat roughly half their body weight per day in good conditions.
For example:
- 500g of worms can process around 250g of food daily.
- 1kg of worms can handle approximately 500g per day once established.
When starting a new wormery, feed lightly at first. Allow the worm colony to settle before increasing quantities. Overfeeding is one of the most common problems in UK wormeries.
If food remains after several days, reduce the amount at your next feeding.
Foods to Avoid in Your Wormery
Knowing what to avoid is just as important as knowing what to feed compost worms.
Avoid adding:
- Meat or fish: These attract pests and create strong odours.
- Dairy products: Milk, cheese and yoghurt cause sour smells.
- Oily or fatty foods: These break down slowly and upset balance.
- Spicy foods: Chillies and heavily seasoned leftovers can irritate worms.
- Large amounts of citrus or onions: Small amounts are fine, but excess acidity can harm your compost worms.
- Pet waste: This can contain harmful pathogens.
In UK homes, it can be tempting to add all food waste to your compost bin. However, keeping your wormery limited to suitable organic matter keeps conditions stable and healthy.
Balancing Greens and Browns
A healthy wormery needs balance.
Kitchen scraps are considered ‘greens’ – they are moist and nitrogen-rich. Shredded cardboard and paper are ‘browns’ – dry and carbon-rich.
Too many greens can cause:
- Excess moisture
- Bad smells
- Sluggish compost worms
Too many browns can slow the breakdown process.
Aim for a balanced mix. If your bin looks wet or smells sour, add shredded cardboard. If it looks dry and inactive, increase vegetable scraps slightly.
Seasonal Feeding in the UK
Temperatures affect how much compost worms eat.
During warmer months in the UK, worms are more active and process waste faster. In colder weather, especially below 10°C, their feeding rate slows.
In winter:
- Feed smaller amounts
- Check more frequently for uneaten scraps
- Keep the wormery insulated if outdoors
Adjusting feeding habits with the seasons helps maintain a steady, healthy worm colony year-round.
Signs You Are Feeding Correctly
Your compost worms are thriving if:
- Food disappears within a few days
- The bedding smells earthy, not sour
- Worm numbers gradually increase
- You see crumbly compost forming
If you notice strong odours, visible mould or lots of uneaten waste, reduce feeding and rebalance with dry bedding.
Final Thoughts
So, what should you feed compost worms?
Stick to fruit and vegetable scraps, coffee grounds, crushed eggshells and shredded paper. Avoid meat, dairy and oily leftovers. Keep your wormery balanced and adjust feeding with the UK seasons.
With the right food and simple care, your compost worms will turn everyday waste into nutrient-rich compost for your garden.
If you are setting up a wormery or expanding your colony, choosing healthy compost worms is the first step to long-term success.