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and Troubleshooting 

  • My Bin is starting to smell...

  • Flies, Ants and other insects

  • My worms are trying to escape

  • Going on holiday?

  • The floor was removed too early and contents have fallen out the bottom

  • The Hungry Bin has fallen over and the contents have fallen out

My bin is starting to smell

If your hungry bin is starting to smell, or the food is rotting before the worms can eat it, add a fine layer of fibrous brown material each time you feed the worms to help balance the bin. You can also sprinkle a fine layer of soil or potting mix into the bin to help balance it. A diet of food scraps can be too rich for the worms unless the scraps already contain plenty of fibre (lots of vegetable stalks for example), in which case you won’t have to add as much to keep your worms healthy and your bin smelling sweet.

The food in the hungry bin needs to have the right ratio of carbon to nitrogen for the bin to be most effective. The ideal carbon to nitrogen ratio for a worm farm is 20:1, however, food scraps can often have a ratio of 12:1. To balance the ratio of carbon to nitrogen, some extra material high in carbon may need to be added to the bin.

Fibrous materials are carbon rich, which also help balance the higher level of nitrogen in food scraps. Also referred to as bulk or roughage – fibre doesn’t tend to break down and rot as quickly as food scraps. It includes paper or cardboard, dead leaves, sawdust or wood shavings, vegetable stalks, old grass clippings (brown).

The bin may also develop an unpleasant smell if it has become too acidic. Sprinkle a small amount of dolomite lime or rock dust on the top layer to help reduce the acidity of the bin. Adding fibre to the food when you are putting it in the bin may also help reduce problems with acidity.

The bin is rotten and smelly, and no live worms are present

It is important to remove any rotting food from the bin as the anaerobic (oxygen-poor) conditions make it impossible for the worms to live. Remove all the rotting food from the bin and set aside. Keep any live worms present in a separate pile to reintroduce to the bin. Once all the rotting food is removed, add a layer of fresh bedding material and any live worms you have recovered. Add shredded paper or cardboard to the bedding to promote even better aeration, and to balance any excess nitrogen causing the rotten smells.

If there are very few worms left, you may need to purchase or harvest more live worms. Restart feeding the bin as normal. It will take some time for the worm population to recover if a large proportion of the worm population has died.

The hungry bin is designed to prevent pests from entering. However, it is a living ecosystem and some small beneficial insects can exist in the bin quite happily. Sometimes these other insects are eating food the worms don't like or prefer not to eat. Insects may also be present in food scraps that are introduced to the bin, e.g. fruit fly larvae.

The food in the bin will naturally attract other creatures. Sometimes insects like white fly are attracted to the bin because the food is too acidic. Try balancing the food with a little lime, shredded paper, dead leaves or sawdust. Covering the food with a hessian sack, old carpet or damp newspaper will also discourage unwelcome visitors.


If the farm is too dry, ants can also establish their nests in the hungry bin itself. Keeping the surface moist will help discourage ants. Ants can be discouraged from enetering the bin by ensuring the bin is not touching a surface the ants can enter the bin from, and then smearing a layer of petroleum jelly on the legs just under the sockets on the lower body.

Fruit flies

The food scraps you have placed in to your hungry bin are very attractive to a host of other critters, not just worms. Normally this is not a problem, but in the warmer months, fruit flies can be an issue. This is especially true if you are eating a lot of fruit like kiwi fruit or bananas which have high sugar levels.

The best way to reduce the fruit flies present in your hungry bin is to ensure that you are adding enough fibre to balance the acidity, and to cover the food with a layer of newspaper or leaves each time you feed your hungry bin. Sprinkling some dolomite lime on the top of the food will also help reduce the acidity that is attracting the fruit flies.

Fruit flies are attracted to rotting fruit or sweet smelling scraps in the bin. Fruit flies will normally be present in the bin, but if you have large numbers it can be unpleasant and indicate that the balance in the hungry bin has changed.

Try burying your food scraps under the top layer. In addition, you can place a couple of layers of damp newspaper flat over the surface. Each of these helps to keep adult fruit flies from accessing the buried food, where they lay their eggs.


Maggots are the larvae of flies. There are many different kinds. The type you may see in your bin will depend on what you are feeding your worms, where you live and the time of year. While many people find maggots unpleasant, they will not harm you or your worms. In fact, they are good decomposers and, like the compost worms, will produce a high-quality casting.

If you haven't added animal proteins, and don't have any foul odours in the bin, then it is likely the maggots you are seeing will be black soldier fly larvae. Once your bin has black soldier flies present, it can be difficult to get rid of them. It may be best to simply allow them to grow out of the larval stage (which they do quickly) and fly off. If you have large numbers present, harvest the worms and get rid of all your affected castings (put them in an outdoor compost pile, or bury them in the garden). Then put your worms back into fresh bedding.


Also known as pill bugs, sow bugs and woodlice. They are beneficial bugs in your bin helping to break down all the compostable material. If you wish to remove them, you could lay damp newspaper on top of the food scraps overnight, in the morning remove the paper with the slaters attached. If you have chickens, you could feed them the slaters. Slaters can also be an indication that the bin is dry so add some water to reduce their population.

Red spider mites

Red spider mites are very common in worm bins. They are usually present when there is a source of bread and protein. These mites can be a problem if you find your worm population depleting. You can remove them by putting in food overnight that the mites are attracted to (like watermelon rind) then remove the next morning with the mites attached and wash them off. Repeat the process until you are satisfied with the result.

Black soldier fly

See Maggots above.


Also known as pincher bugs, these are harmless creatures in the worm bin. They generally indicate a slightly acidic environment, which can be remedied easily by adding a handful of garden lime.

White worms

Also known as pot worms or grindle worms. They will not harm your worms but can be an indication that the bedding is too acidic. Add a handful of dolomite lime or garden lime.


These little arthropods feed on composting material but are also known to feed on small insects including the odd worm. Best to evict these visitors as you see them. Watch out for their pincers!


These omnivores are attracted to food scraps. Avoid putting in any meat products. They also like dark tight crevices so you could uncover the bin for periods of time, which will make the worms work at lower levels and discourage the cockroaches from taking up residence. However, keeping the lid on in the first place will prevent them entering. To get rid of cockroaches without using baits you could try a 1:1 mixture of baking soda and sugar. Spread it around the outside of the bin.

Flies, Ants and other insects
My worms are trying to escape

The hungry bin can be left for two to four weeks without fresh food. Adding shredded paper, dead leaves or dry lawn clippings to the food for a week or two before you go away helps the food last longer. Water any dry material you add to your hungry bin to ensure the bin doesn't dry out while you are away.


If you are going away for a month or two, it’s no problem either. All you need to do is alternate layers of leaves, dried grass clippings, shredded paper with alternate layers of food scraps. A total of 30 cm will last for a couple of months without too many problems. If you are away for longer, you may need to ask a friend to feed your farm while you are away.

Alternate layers of food scraps with the other material you are adding. This prevents the layer from going rotten and smelly while you are away.

Going on Holiday?

The tapered shape of the hungry bin compresses the castings as they move down through the bin. When the floor is removed, only the castings at the very bottom of the bin should fall out, as the remainder are held in place by the shape of the bin. If the castings in the bin are not sufficiently compressed when the floor is removed, some, or all the material in the bin will fall out. Usually this happens because the floor has been removed too early, or before the castings or bedding material have become compressed.

It is also an advantage to allow the bin to become full to the top with finished castings before removing the floor. A full bin is less likely to have problems as the volume of the castings helps moderate the bin, and prevent problems.

If the contents have fallen out completely, reinstate back into the bin in the same order that they came out of the bin, with the oldest material to the bottom, and the live worms at the top.

If only some of the material has fallen out, but the majority of the castings are still in the bin, replace the floor back onto the bin, and simply return the castings that have fallen out to the top of the bin. Placing finished castings in the top of the bin will not affect the worms present in the bin, but you may need to wait for the worms to migrate to the surface again before you can feed the bin at full capacity.

The Floor was removed too early

Get the bin back into an upright position. Reinstate the material that has fallen out – in the same order it came out in if possible – with finished castings toward the bottom and live worms on top. You may need to wait a few days before feeding the bin again as the worms will not all be present at the surface of the bin.

The bin has fallen over and contents have fallen out
My Bin is starting to smell
Flies, Ants and other Insects
My worms are trying to escape
Going on holiday?
Floor removed too early
The Bin has fallen over

The hungry bin is a living ecosystem. It is important that ideal conditions are maintained in the bin for it to operate most efficiently. Maintaining ideal conditions in the bin is easy – simply follow these basic rules:

1. Feed the bin a maximum layer of 2.5cm (1in) at any time

Do not overfeed your hungry bin. Spread the food evenly over the top layer of the bin. You should not feed the bin more than 2.5cm (1in) per day. 

2. Uneaten food should be no more than 5cm (2in) deep at any time

Do not allow uneaten food to build up in the bin. If uneaten food has accumulated, it will begin to rot. Rotten food is acidic and putrid, and worms will not eat it.

3. Add fibre and/or lime occasionally to help balance the acidity of the bin 

Adding some fibrous material such as shredded paper or cardboard, dead leaves, sawdust, old grass clippings (brown) or a sprinkling of lime or wood ash when you feed the bin will help reduce the acidity, and keep the bin smelling sweet.

4. Avoid large quantities of processed and/or acidic food 

Processed food, like bread or pasta, can quickly become acidic as it decomposes. Large amounts of acidic foods such as lemon rinds, onion and fruit skins should also be avoided.

5. Only harvest castings when the bin is full 

Castings should only be removed when the hungry bin has become full to the top of the taper.

Sometimes worms will cluster at the top of the bin, and on the underside of the lid, if it is about to rain. This is a natural response to prevent them from drowning in the wild, or to migrate to fresh food when the ground is wet. They will return down into the surface layer when the rain has passed.

If the conditions in the bin are unfavourable the worms will also try to migrate. This is usually caused by overfeeding, or if the food has become too acidic. However, if you keep the lid on as recommended, it is almost impossible for them to escape. Occasionally a worm may fall from the bin into the drip tray, especially if castings have recently been removed.

If the food is too wet the worms will look fat and pale. Add some dry leaves or shredded paper. Gently use a fork to turn the top layer and create some drain holes on the surface.

If heavy rain is flooding your bin try moving it to a more sheltered location.

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