What to Put in a Compost Bin (and What to Avoid)?

Composting is one of the most effective ways to reduce household waste and enrich your garden soil naturally. But many people starting their composting journey are unsure about what can actually go in a compost bin - and what should be kept out. Getting the balance right is key to creating nutrient-rich compost without attracting pests or creating bad smells.

What You Can Compost: The Greens and The Browns

Composting works best when you balance two main types of material: greens (nitrogen-rich materials) and browns (carbon-rich materials).

Greens include:

• Vegetable and fruit scraps (peelings, cores, banana skins)
• Coffee grounds and tea bags (remove any plastics if bags aren’t biodegradable)
• Grass clippings
• Plant trimmings and green leaves
• Eggshells (crushed)

Browns include:

• Cardboard and paper (shredded - but not glossy or printed paper)
• Straw and hay
• Dead leaves
• Very small amounts of sawdust and wood chips (see our blog about using these in composts)

Keeping the right ratio - roughly 25:75 green/brown or 50:50 green/brown - helps ensure your compost decomposes effectively.

What to Avoid Adding

Not everything from your kitchen or garden is suitable for composting. Avoid the following items:

• Meat, fish, and bones (only add in very small quantities as they are hard to breakdown)
• Dairy products - these have a high moisture and fat content which can slow down the composting process.
• Cooked foods or oily leftovers - for the same reasons as above
• Dog or cat faeces (due to pathogens) but could be added to compost if used only on non-edible plants and after a long period of composting.
• Glossy magazines or coated paper (small quantities are fine but can upset the balance of your compost)
• Coal or barbecue ash as these can contain chemicals or heavy metals that could contaminate the compost

These items either slow down the composting process, release unpleasant odours, or pose health risks so add with caution.