HOW TO SET UP A WORM COMPOSTING SYSTEM
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SETTING UP A SYSTEM
Of the commercially available worm composting systems, most are designed by worm farmers and work very well.
If you are thinking of buying a system, first consider how much material you have to compost. You may be surprised. Pile up for one week, all the organic material you would normally throw out. If you intend to compost it all, you will most likely need one of the larger systems and these can become quite expensive. However, to build your own system need cost you very little and you can tailor it to your own needs and build it out of what you have or can get cheap. What size to build.
This is your first consideration because it will effect how much material you can compost and also the site where you can put it. As a guide, an average family of four with household waste, a lawn to mow, garden clippings, a daily newspaper, junk mail and a couple of pets will need a system of about one cubic meter if they are to compost all their organic waste, but if you are aiming to compost just kitchen scraps you will only need the size of a garbage bin. Make your system a comfortable height especially if children are to help with the composting; anything from 50-150 cm will do. You can make it wide but don't make it so wide that you can't reach the middle.
Another consideration when designing your system may be a lid. In most circumstances, a lid is not necessary and not recommended but in areas where the piling up of snow is likely, a sloping lid will solve the problem but do not make it airtight. Flies are another reason to fit a lid. In this case a finely screened lid will do and will also help to shade the system. If trees overhang, you may have a problem with cats, possums or other tree-climbers getting into the system which a lid would deter. In all cases, make the lid easy to operate and with adequate air-flow. Selecting the Site
There are several aspects to consider when locating your system. Convenience is important because if it is tucked away right up the back yard, chances are you won't always use it. A protected place away from strong winds and direct sunlight is best. It will need to have a water supply and somewhere for the runoff (which will be liquid fertilizer) to go. Under a large shrub with the runoff directed towards a garden or lawn is ideal. The area around your compost will become extremely fertile so, if possible, use this to advantage. A level area is preferable and if this means digging into a slope it is quite suitable but do not set up the system in a pit as water may build up in it. It’s best to keep it out of access to curious toddlers and dogs. Also be aware that, like all composts, it may attract vermin and scavenging birds or reptiles.
A climate-controlled situation such as a shed, carport or verandah is excellent but remember there will be liquid runoff to collect or direct.
Drainage
The system needs to be kept moist but not soggy, about 30-40%. Stale water trapped in the system will poison worms and they will retreat if it is too dry.
If the system is located on a slope and the surrounding soil will allow seepage, it can be positioned straight onto the ground. If the site is level or in a dip, use bricks, large stones, scoria or gravel built up to about 10-15 cm deep and extending at least 10 cm beyond where the sides will be.
If vermin is a problem in your area, bricks are preferable as mice and rats can't dig through them.
Constructing the sides.
A worm composting system can be as simple as a heap on the ground but in a suburban situation this is not recommended. Sides will not only contain the system and keep it neat but also keep vermin and other pests out, stop dogs and cats from digging in it, minimize evaporation, prevent odors and make it childproof.
Sides need to be rigid, durable and of a height that is comfortable to use. In extreme climates, some kind of insulation should be considered such as a layer of polystyrene. Unless lined with strong plastic, wire or plastic mesh is not satisfactory, as the worms will not operate around the sides. (Worms retreat from light and also the sides tend to dry out in a mesh-only system).
There are two ways of removing the castings from the system and this has to be considered before starting to build. The castings will always end up on the bottom of the system. To remove them you either have to dig them out from the bottom or let one system 'finish' while starting another..
Whatever the size and design of your system, the sides are what you will see so you may want to use an attractive material to complement your garden.
Some of the many materials you can use are:
* Timber. A square construction is simple to build. The timber can be new or secondhand but don't use softwoods and avoid treated timber products containing poisonous chemicals. Because timber is heavy, a removable bottom section or side is recommended for collecting the castings.
* Stone, brick or concrete. For a system that will last forever, stonework, brick or concrete sides work very well. They require sufficient drainage holes or slits built in and these can be screened to deter vermin. These systems need to be shaded through Summer as heat builds up in these materials.
* Shipping containers. A timber shipping container is a ready-made choice; a cubic meter container being particularly suitable for the average family. The timber ones have natural drainage through the bottom but the bottom may collapse after a few years so drainage directly under the system is still required.
* Sheet metal. A circle of sheet metal is probably the simplest system you can build. Simply bend a length into a circle and rivet or bolt the join. Galvanized metal won't affect your worm population but be aware it may leach some chemicals into the castings which is unfavorable if you are to use the castings for food produce. To empty a finished sheet metal system, simply undo the join and you will be left with a large 'cake' of castings.
* Plastic. Synthetic materials are suitable for sides provided they are rigid. Strong flexible plastic can be used if supported by a wire or mesh frame. An old rubbish bin turned up-side-down with the bottom cut out will do. Plastic is light, so it is easy to lift up or off to remove the castings.
* A regular compost bin. Excellent, but throw away the instructions. All regular compost bins can be converted for worms and represent an easy alternative to building a system. They come in all kinds of sizes. The timber ones will need a detachable side or bottom panel but the plastic ones, because they are light, can be lifted up or off to remove the castings.
Preparation for Bedding
When worms are introduced to a new system, the first thing they will do is explore, so to prevent them from wandering, lay a temporary barrier. The best thing to use is enough whole newspapers, well-soaked in water, to cover the bottom of the system. You could also use natural-fiber carpet or under-felt or anything else of a similar nature that the worms will eventually eat. Simply lay this barrier straight over the drainage, whether it be rocks, bricks, slits in a stone wall or whatever, and bring it up the sides a little.
That is the only preparation you will need in a small system or one that will have a whole side removed or be removed completely to get the castings. However, in a large or deep system with a detachable bottom panel for removing castings, it is recommended to install a grate.
The Bedding
The most important part of setting up a worm composting system is the bedding. This is where the worms will retreat from the heat and rancidity of the rotting waste. Their health and the success of your system depends on good bedding.
Be generous. Make it about 30% of the depth of your system when dry and loosely packed. Don't physically compact it.
The best medium for bedding is 'live castings' which are available from some worm farms. If they aren't readily available, use any of the following:
* Finished castings from a worm farm or another worm composting system.
* Regular finished compost that is completely cooled. The best way to check for coolness is simply to bury your own hand in it. If it is comfortably cool to you, it is comfortable for the worms.
* Aged manure. Horse, cow, pig or other large livestock manure is best but must be aged to the point where it is cool and then thoroughly leached. Intestinal worm treatments for livestock also kill earthworms but will neutralize in the manure after about one month so be sure any manure you use is at least one month old if you don't know its origin. Poultry manure is less suitable but can be mixed with leaf mulch or old compost.
* Light, friable soil. It is best mixed with shredded paper or sawdust to give it a bit more airiness.
* Leaf mulch. It may contain a lot of small sticks which are unlikely to break down completely but can easily be raked out of your first castings if necessary.
* Coir (coconut fiber). Coir can be bought as a brick which, when soaked in water, swells to a good consistency for worms.
* Organic potting mix. Don't use a potting mix that contains chemicals.
It is important with any bedding that it doesn't contain too much fresh food value because it will create heat and poisonous gases as it decomposes.
Once you have the bedding in place, give it a thorough soaking, turning continually to be sure it is wet through, then leave it for a short time while the excess water drains off. You should be left with a comfortable moisture content and the bedding will have compacted a little. You are now ready for the worms.
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Buying and Introducing the Worms
Worms are best purchased from a reputable worm farm. Some worm farms have a mail-order service. This can be very convenient if you don't have a farm close by.
If purchasing from a nursery or retail outlet, be aware the worms could have been on the shelf for a while, sometimes months. If there is any unpleasant odor, don't buy them. Sick and dying worms smell dreadful and you will notice this smell if deterioration has even slightly set in.
Worms are usually sold by weight as bulk worms. 250g of compost worms will be around 1000 worms depending on their size. This would be a minimum amount to start with in a small system. They are cheaper by the kilo but the best way to purchase worms for composting is to buy a 'worm colony'. Not all worm farms will have them but if possible, choose this option. A worm colony will have been established for several weeks. In this time the breeding worms will have produced many thousands of babies and eggs to give you a quick start. The more worms you start with, the quicker the population in your compost will 'explode'. Be sure you buy compost worms. Worms sold for fishing are usually earth workers and will not thrive in a nutrient-rich environment. By all means keep them in your compost to breed for fishing but they won't do much composting. The usual breeds sold for composting are reds, tigers, blues and composting 'locals'. All these worms work vertically in the system, creating vertical burrows between the rotting waste and the safety of the bedding. There are various species in each category. By purchasing worms from a worm farm, you can be sure the worms will breed well because a worm farm relies on breeding rates to be viable. .
A mix of worms is best. Not all types of worms will do well in all areas and some will hibernate in some areas. The chance of getting unsuitable worms is very unlikely with a mix.
Either way you purchase your worms, it is best to introduce them in the morning, at latest early afternoon, even if it is a dull day. This will give them plenty of daylight hours to establish their initial burrows. If you put them in towards night, they may be disoriented and start to climb the sides of your system. Once the worms are settled, you can start adding waste. Don't start with too much as there will most likely still be food value in your bedding. If your waste is piling up, simply let it compost naturally while the population of worms grows. After a few months, depending on how many worms you started with, you will have trouble filling your system. The worms will eat everything as quickly as you add it, but be patient getting to this stage, while worms breed quickly, they can't perform miracles overnight.
What Waste to Feed Your Worms.
Worms will eat almost anything organic, i.e. once living but they will also process partly inorganic materials such as printed paper and cardboard. If you are looking to produce a 100% organic vermicast for growing foodstuff, it will be best to run two systems; one that you just put in 100% organic material and the other for general use such as on flower gardens and lawns. Most chemicals will eventually be broken down after passing through worms several times and are likely to be all but gone by the time you collect your vermicast but don't take the risk of feeding your worms chemically treated waste if your ambition is to grow 100% organic produce.
In a small or medium system, large pieces of waste such as cereal packets and cardboard boxes will need to be broken up for peak efficiency but in a large system, because time is on your side, they can be thrown in whole. Any dry materials such as paper, cardboard, fabrics and leaf mulch are best soaked in water before adding but it's not completely necessary with regular watering of the system. The following types of waste are all suitable for your worm composting system:
* Kitchen scraps, for example: vegetable peelings, apple cores, banana skins, rotten fruit, carrot tops, leafy waste, left-overs, stale bread, tea bags, coffee grounds. Citrus peels break down more slowly than average but put them in. Don't forget liquid waste such as cooking water and oils, left-over soup, tea and coffee dregs. Cooked vegetables, rice and pasta process quickly but when uncooked they take much longer.
* Meat. Worms love meat but wrap scraps in paper before adding because it attracts flies and it smells. Bury it down a bit. * Paper waste. Junk-mail, newspapers, magazines (the glossy ones take longer to break down), writing paper, computer paper, torn up phone books, cereal and other food packaging including milk cartons (some food packaging, especially frozen food, has a plastic membrane which won't break down), cardboard boxes, egg cartons. With food packaging and boxes it is a good idea to fill them with food scraps as the worms love these 'havens' in the compost to explore and breed in before they're eaten.
* Soft garden waste including lawn clippings, leaves, leaf mulch, flowers, weeds, dead plants and finished vegetables. If putting in a large load, wet thoroughly through, especially grass clippings as they produce a lot of heat.
* Manure and pet poo. If an animal has been 'wormed', let the droppings age for at least a month before adding. The worming effect will neutralize in this time.
* Kitty litter. If your cat or dog uses a tray, buy the litters that are made from recycled paper as these will process in your worm compost.
* Vacuum cleaner waste but only if you have a natural fiber carpet. Synthetic fibers in the compost will not process and you will wonder what the fluffy balls are in the vermicast. Lego blocks don't process either!
* Fabric, rags and old clothes. Any natural fiber fabric including hessian, cotton, wool, hemp and even wool carpet.
Some organic material is less favorable for worms and they may take longer to process it. It is best to avoid these materials, especially in a small system:
* Chunks of fat
* 'Hard' waste such as woody onion skins
* Twigs
* Large pips and nuts
* High concentrations of acidic waste. Mix with other materials.
* High concentrations of hot, spicy waste such as chili peppers.
Collecting your scraps needs to be easy and convenient. Garden waste can go straight into the system but for kitchen and paper scraps, the best idea is to have a large bucket with a handle and a lid next to the rubbish bin. Quarter fill it with water so that paper can go straight in and be soaked at the same time. You can put all your liquid waste into it as well. The lid will stop any smell escaping and it can be easily carried to the compost when full.
Unless you have plastic, metal and glass recycling services, get into the habit of purchasing products with organic packaging. Over a year, this will save mountains of waste otherwise destined for the tip.
Once your population of worms has 'peaked', you will be amazed at just how much they will eat. They will consume a total of 50-100% of their own weight every day. Although this amount includes some reworking of castings, in a cubic meter system it is not unusual to see the system literally 'drop' in 24 hours. It will become increasingly difficult to fill the system but the time will come when the depth of castings builds up to a point where the worms have less space per worm to breed in the favorable temperature range and the population will start to drop off. At this time, the system will be near to full and it is time to let it finish or collect castings from the bottom.
Covering the System
While a lid may or may not be needed, the system will need a cover. This is best made of old synthetic carpet. It will last for years and absorbs water and aerates equally as well as natural fiber which would get eaten. The purpose of the cover is to minimize evaporation and protect the system from predators and the elements. It will also encourage and extend surface feeding time. Without a cover, the worms will not venture to the very top but under their protection, they will feed, mate and drop castings. Castings have a natural deodorant effect so this will help eliminate stench from newly composting material. You will also get to see your worms and know that they are healthy.
Cut the cover to fit snugly, right up to the sides of your system whatever its shape. The cover needs to be lifted each time you add scraps so it is a good idea to have some handles. Handles make the system cleaner and safer to use as there is no risk of your hands coming in contact with rotting waste or undesirable critters such as spiders. Simple cut a pair of holes in the cover and loop through some synthetic string or wire. Watering the System
Fresh water is essential. Through the rainy months you may not need to water it at all but always be sure any fresh waste is soaked. In drier weather, however, a weekly watering is necessary. Do not direct a torrent of water into the system but sprinkle evenly. This will prevent water damaging the worms' burrows or eroding the system down the sides.
There is no risk of over-watering if your system is well drained but try to keep it moist, not soggy. If worms are congregating in massive swarms on top of your waste and you don't suspect any other problems, you can assume you have a soggy system. Simply dry it out for a while and things will return to normal. Will Worms Escape?
You now have a system that will provide the ideal conditions for worms. As worms rely wholly on instinct, if they are comfortable, well fed and feeling healthy, they have no reason to move. Although some might make their way through the bottom of the system, you will have a lot more coming in than going out! The locals will soon find their dream home and start moving in.
Most 'guests' will be earth workers from your garden. They will find perfect breeding conditions in the lower castings of your system and will operate horizontally improving your drainage and populating your castings with the exact worms that thrive in your particular garden.
Depending on the environment around your compost, some local composting worms will also make their way in. This is a tremendous advantage as these worms will complement any commercially available mix and boost your population.
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