This free worm bin planner helps you size a worm bin from weekly kitchen scraps, choose bedding, and get a feeding schedule for the worms. Worms eat best when the bin matches the food supply: too much food rots before they reach it, and too little food leaves a hungry, shrinking worm population. It runs fully in your browser, so nothing you type is sent to a server. You need no account and no sign-up to use it.
A right-sized worm bin turns kitchen scraps into rich castings with almost no smell and no garden space at all. It suits flats and small homes, where a hot compost pile is not possible, and it gives seedlings a gentle feed that never burns roots.
To use the tool, fill in the boxes on screen and press the calculate button. You can change any number and calculate again as often as you like. The result updates at once, so you can test different plans side by side and see which one fits your garden best.
For example, take 3 kilograms of kitchen scraps a week with straw bedding. The tool shows a 75 litre bin, 1.5 kilograms of worms needed, and 3 feedings a week. Drop to 1.5 kilograms with shredded paper bedding and the plan shrinks to a 45 litre bin with 2 feedings a week.
Worms slow down in cold weather and eat less, so feed smaller amounts in winter even if the summer plan says more. In summer heat, keep the bin in shade, because worms suffer fast when bedding passes 30 degrees.
Tip: Bury each feeding under bedding. Exposed food draws fruit flies, while buried food stays clean and worm-friendly.
Tip: Avoid citrus, onion, and garlic in large amounts. Small bits are fine, but big loads upset the bin and drive worms away.
Tip: Keep bedding as moist as a wrung sponge. Dry bedding stops worms feeding, and soggy bedding turns sour fast.
The most common mistake is overfeeding a new bin. Fresh worms need weeks to settle and multiply, so a full weekly load in week one rots before they can eat it. Start with half rations and raise the amount only when each feeding disappears cleanly.
Common question: What worms should I buy? Red wigglers are the standard composting worm. They live near the surface and eat food scraps fast.
Common question: Can a worm bin live indoors? Yes. A well-kept bin has no smell, which is why flats and kitchens suit worm bins so well.
Common question: How fast do worms multiply? Given food and steady moisture, a healthy population can double in a few months.
Flat dwellers, families with small kitchens, and school classes learning about food waste use worm bins. They also help gardeners who want castings for pots and seedlings without a full compost heap.
Keep a note of your pile dates and results through the season. After a few months you will see which mixes heated fastest and which plans finished on time. That record is worth more than any guess, because it comes from your own garden and your own waste.
Before you build the pile, read your plan once as if you were doing it tomorrow. Do you have the browns, the space, and the dates clear? If anything looks unclear, fix that line before you start. A plan that needs no guesswork works far better than a bigger plan that confuses you.
This tool is free to use as often as you like. Bookmark it and come back whenever you start a new pile or plan a harvest. A clear plan helps you compost with less smell, fewer flies, and more finished compost for your beds.
Remember that every result here is an estimate for home composting, not professional advice. Your local climate, your waste mix, and your bin type all shape the real result, so use the tool as a starting point and adjust it to your own garden.