What are compost worms?
Unlike earthworms, compost worms do not make burrows in the soil, but live in the surface layer (the top 30cm or 12in). They have evolved to eat rotting plant matter on the forest floor, and are perfectly suited to break down organic waste. Compost worms are generally smaller than earthworms. Tiger worms (Eisenia foetida), Red worms (Lumbricus rubellus) and Indian blue worms (Perionyx excavatus) are the most common worms used for composting.
Should I add water?
Generally you should not need to add water to the hungry bin. Food scraps have a high water content, which helps keep the bin moist. The design lets excess water drain from the bin, but ensures enough moisture is retained to maintain optimal conditions. The worms do need to be moist though, so if the bin has dried out, sprinkle a little water on the top of the bin. If you have added dry matter like shredded paper you may also need to add water. Take care not to drown the worms, the top should only be as wet as a wrung-out sponge.
How much liquid should my bin produce?
The bin will produce about half a litre (one pint) of liquid a day when it has a full worm population and is fed regularly. It is important that the liquid is free to drain from the bin at all times. If liquid from your bin is not collecting in the drip tray, it may be too dry. See Should I add water? above. The filter tray may also have become blocked with paper or plastic if this has been placed in the bin. Remove the floor and check the filter. Check that the bin is not exposed to intense sun for long periods and move to a shadier spot if necessary. The liquid fertiliser should be mixed 1 part with 10 parts water before being sprinkled onto the soil around plants.
Going on holiday?
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 freind to feed your farm while you are away.
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.
How do I setup my Hungry Bin?
- place bedding in the bin - moisten the bedding with a little water - add worms - add finely chopped food scraps - cover with damp newspaper Bedding material is needed to settle the worms into their new home. Compost, soil, potting mix, coconut fibre, dead leaves or shredded paper can all be used to bed the compost worms into the bin. Take care to ensure that the bedding material you use to start the bin is free draining. Place the bedding material directly into the bottom of the bin. For best results place at least 75 litres of bedding (3/4 Full) into the bin. This is the equivalent of three 25L bags of compost or potting mix. If you have sufficient bedding material available, you can fill the bin to the top of the taper before you add the worms. Moisten the bedding material with some water, but don’t saturate it. The bedding should be as wet as a wrung-out sponge. Add the worms to the top of the bedding material and cover with approximately 2.5cm (1in) of food scraps (preferably finely chopped). The amount of food you add each day will depend on your starting worm population. Approximately 2000 adult worms (or 500gms) is a good number to start your bin. However, the more worms you start with the faster the bin will reach maximum capacity. A full population is approximately 16,000 worms, or 3kg (6.5lbs) of adult worms. It takes about six to eight months to breed a full population from a small starting population. As the population grows it will regulate its numbers to match the food supply. Your bin will not become overpopulated. The number of worms in the bin will be determined by the amount and type of food you feed the bin. Similarly, there is no minimum amount of food you need to feed the bin each day. As long as the bin is fed regularly, and you follow the feeding guidelines, the bin will operate without problems. You can cover the worms with damp newspaper, sacking or old carpet to encourage them to come to the surface. Keep the lid closed as worms don’t like direct light – the lid is also designed to prevent insects from getting into the bin.
What can I feed my worms?
Compost worms benefit from a balanced diet. They will eat most normal kitchen fruit and vegetable scraps. Avoid feeding the worms large quantities of meat, citrus, onions and dairy foods. Some processed food also contains preservatives, which discourage the worms from eating it. These foods won’t harm your worms, but they will avoid them and those scraps will break down and rot in the bin. The worms will eat their preferred food first but like to have some variety. The smaller and softer the scraps, the easier it is for the worms to digest and process them into castings. Likes Most fruit and vegetable scraps Pulp from the juicer Cooked food Tea leaves/bags and coffee grounds Crushed/ground eggshells Hair, vacuum cleaner dust, soiled paper, tissues, handy towels, shredded egg cartons, toilet roll inners, paper lunch wrap Shredded moist newspaper & cardboard Lawn clippings in small quantities (spray free), weeds, clippings, prunings, dirt and leaves Sawdust (untreated), wood ash Dislikes Fats or oils Citrus, acidic fruit skin Spicy foods, onion, garlic, leeks, capsicums Shiny paper Meat and dairy products Bread, pasta and processed wheat products Compost worms will also eat garden or yard waste, and animal manure. If adding lawn clippings take care to only add a little at a time. Fresh lawn clippings can heat up and cause problems. If you do place animal manure in your bin ensure that the animals have not been treated with anti-worm medication, as it may still be effective in their dung! It is also not advised to use dog or cat droppings if you intend to use the castings in your food garden, as the animals may have gut parasites, which can potentially infect humans.
What about manure ? Dog or cat poo?
Compost worms will also eat animal manure. If you place animal manure in your bin ensure that the animals have not been treated with anti-worm medication, as it may still be effective in their dung! It is also not advised to use dog or cat droppings if you intend to use the castings in your food garden, as the animals may have gut parasites, which can potentially infect humans.
How much can I feel my worms?
It is very important that the hungry bin is not overfed. A fully functioning bin will have up to 3kgs (6.5lbs) of compost worms. They prefer to eat their food as it begins to decompose, but not if it has become slimy and smelly. If the bin is overfed, the food scraps will begin to rot before the worms can eat them. Rotting food scraps not only smell, but also interfere with the lifecycle of the worms and the operation of the bin. Rotting food is anaerobic – or oxygen deprived. Because worms breathe through their skin, anaerobic conditions prevent the worms from breathing properly, and may cause them to die. Worms can eat roughly their own body weight in food a day, so make sure that you only add about the same volume of food each day as there are worms. Start by feeding the worms a small amount of food each day. Each time you feed the bin, check that uneaten food is not accumulating. You could chop up large food scraps into small pieces – the smaller and softer the scraps, the easier it is for the worms to digest and process them into castings. Slowly increase the amount you feed the worms as the population multiplies. The worms will breed and increase in numbers to match the food supply. Building up a full population of worms (about 3kgs) can take up to six months. A good rule of thumb is that uneaten food should be no more than 5cm deep. You can check this by digging through the top layer of the bin and checking how deep the uneaten food is. In a healthy bin finished castings should be present 5-10cm (2-4in) below the top layer. You should also be able to see a mixture of adult and juvenile worms, indicating that the worms are breeding. If uneaten food is building up, simply stop putting new food into the bin until the worms have eaten the food present. Approximately 20cm (8in) below the surface the food should have been completely converted into worm castings. Finished castings look like high quality compost and have very little smell. Worm eggs should also be present in the castings immediately below the food layer; signifying conditions are ideal for breeding. The worms need to be able to lay their eggs in fresh castings immediately below the food they are eating. If the bin is overfed and a layer of rotting food has formed, the juvenile worms will be unable to move upwards through the rotting layer to the fresh food when they hatch, resulting in the population declining. To remedy a build-up of rotting scraps, you may need to gently fork a small amount of fibrous material into the top food layer. In extreme cases the rotting food will need to be removed completely and the bin restarted, as rotten food can take a long time to break down in the bin.
How do I harvest the castings?
- Remove the drip tray and pour any liquid there into a suitable container. - Release the latches securing the floor to the lower body. - Lower the floor from the bottom of the bin. The floor should be full of finished castings. - Tip the floor upside down and tap sharply to knock out finished castings. - If needed, clean the filter with a hose or some water. - Replace the floor over the lower body and secure in place with the latches. Some worms may be present in the castings. The worms can be easily separated from the castings by spreading them on the upturned lid, and placing it on top of the bin. The worms present will retreat from the light deeper into the castings and the top layer can be removed. The separated worms can then be tipped back into the bin. Plants have evolved to uptake the nutrients created by worms – their castings are one of the most beneficial fertilisers for plants. Castings are pH neutral, so are very safe to use with all plants. Even a small amount of castings or liquid added to soil will improve the performance of plants. They can be used in the same way you use compost, or heaped around plants. Pure castings may burn the roots of small plants if used undiluted. For use on smaller plants it may be necessary to mix the castings with other soil first. Castings should only be removed when the hungry bin has become full to the top of the taper. Removing castings before the bin is full will affect how much food the bin can process. The hungry bin needs to be at least ¾ full of finished castings to work most efficiently. This is to ensure the finished castings in the lower part of the bin have been cured completely, and are fully compacted. When the floor is removed, the shape of the bin means only the castings in the bottom part of the bin will fall out. When the castings have been properly compacted and had enough time to consolidate, they are largely free of worms and clump together, making them easy to remove and handle. If the floor is removed before the castings have become properly compacted, all the material present in the bin, including the worms, will fall 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 juice is evaporating
If you are not getting much liquid it may be evaporating before you get a chance to use it. In this case you can place a suitable jug or bottle under the floor to catch the juice. Placing a funnel in the neck of a bottle will help catch the juice.
My worms are trying to escape
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.
What's so great about a Hungry Bin?
The hungry bin is a continuous flow system. When operated correctly, continuous flow systems are far more efficient than worm farms that use stacked trays. The unique shape of the bin creates a large surface area allowing all the worms living in the hungry bin to easily access the food scraps at the top – exploiting the fact they’re surface feeders, and increasing their processing capacity. The tapered sides also encourage the worms to stay on the surface, while compressing their castings below. Once the compost process is complete, the hungry bin is designed to allow the simple and easy harvest of both finished castings and liquid fertiliser. Harvesting castings does not involve any heavy, messy lifting. The floor of the bin is easily removed, allowing approximately 4 litres (3/4 gallons) of castings to break away at the bottom of the taper. This allows the easy removal of finished castings from the bin. Removing the castings is a relatively clean process. Finished castings are largely free of worms. The lid is at a comfortable operating height, and convenient to open and close. Tight fitting, it prevents pests from entering but has sufficient venting to create healthy airflow. The hungry bin even has wheels, making moving the bin light work.