Worm farming, all you ever wanted to know and more.

There are 2 well researched,  scientific ways to produce safe and beneficial compost, and a worm farm is one.....

 Worms will only migrate away if they are not fed and watered. Neglect them and one rainy night they will up and leave.  The worm is a wonderful creature who wasn't always appreciated till Charles Darwin pointed out to the Victorian era folks who believed worms were harmful, that they need not remove them from their pot plants.Indeed the worms manure makes plants grow superbly.

Note the size of the matchbox in both these pics and the verdant green colour of the calendula plant grown  in the worm castings above.

Calendula without castings

 The worm is a predator which feeds not so much on the old lettuce leaves we toss in, as on the multitude of micro organisms that come to decompose that organic matter. The worm eats bacteria and fungi and the protozoas, microarthropods and nematodes which prey on that bacteria and fungi. Worms have a crop which grinds up their prey , releasing  cytoplasm . Worms have an extraordinary ability to destroy pathogens such as e coli, which does not survive passage through the gut of a worm or even exposure to the slime on a worms body .

 Worm manure or castings are free of pathogens and full of beneficial bacteria. The worm has a culture chamber in its rear end which innoculates material passing through the worm with good bacteria, such as bacillus serenade and  Pseudomonas. Some members of the genus Pseudomonas are able to metabolise chemical pollutants in the environment, and as a result can be used for bioremediation. You can detoxify land contaminated with DDT and dieldran using worms. Dr Elaine Ingham has detoxified a property in 3 months using compost tea made from worm castins, which is pretty cool....it normally takes 500 years.

Worms eat their own weight every day, reducing putrescent waste to valuable soil.

Worm populations will grow to cope with any size mountain of waste presented but will need time to build up in numbers. Less time in summer and autumn when temperature is mild and humidity high. 27 degrees C is optimum for worms, who will eat at the surface and happily grow to mating age, or should I say weight. When a worm attains a certain weight it will grow a band around its middle which allow it to have sex with other worms and make capsules.Each capsule or egg may have several baby worms emerging from it.

A worm exposed to ultraviolet light is a stressed worm and after 15 seconds in summer.....is a dead worm.

Two disadvantages with worms over thermo composting is they do not destroy weed seeds, and only operate within a temperature range of between about 17 and 27 degrees, rather like me. They will not be active during dead winter nor happy in high summer. Provide a good foot of bedding soil for them to burrow down into at such times but no deeper as a greater depth getting excessive weighty and soggy could cause the deadly anaerobic conditions we strive to avoid. Anaerobic conditions create habitat suitable for plant pathogens (egs: fusarium, rhyzoctonia, pythium ( damping off), Phytophthora (dieback)) and human pathogens (egs: salmonella, chigella, lysteria, etc) as well as the harmful microbes metabolites like acids, alcohols , formaldehyde. Yuk! Under low oxygen conditions beneficial microbes go dormant, but if the oxygen drops too rapidly they will die. Then their bodies will lyse, releasing their valuable nutrient. We will lose minerals as smelly gasses. Where oxygen drops below 6 ppm, Nitrogen is lost as ammonia ( NH4), elemental sulphur is lost as hydrogen sulphide ( H2S) and valuable phosphorus is lost as odourless but glow -in -the -dark phosphine gas ( PO4).

There are 2 ways to worm farm, continuous flow and batch culture.

Batch culture

For this you need a worm bin with holes in the bottom. 

 . Your worm farm is best sited in a building which will moderate extremes of temperature, but failing this, make your container from the better R Value materials, and choose a site which is not too exposed to the extremes of climate. You should be able to reach it with a water hose . It could just be 4 sleepers in a rectangle, or be made with low brick or urbanite walls. You could use an old bath ( not chipped enamel as this is a lead contamination hazard), better still an old fridge . Fridges are insulated,and have nice fitting lid (the door). Hack a drainage hole into the back and lie it down on its back in the shade of a deciduous tree , then create a few small, flyscreened air holes near the lid, so there is a nice air flow.

Worms will eat anything that was once living . For example: kitchen scraps,old flowers,hay, woodchips, feathers,cardboard, grass and hair clippings, dead rabbits, fish scraps,seaweed, saw dust and wood shavings or chips.See recipe below for proportions. You need a cover to prevent ingress by worm predators such as chooks, other birds and rats, and to keep moisture levels right ( more on that later. If you have a large expired pet, such as a cow, you have a big problem which will go anaerobic. If possible the deceased  should be diced up (this goes for all materials actually, the more surface area the better) but failing this at least prod the carcass vigorously with a garden fork while no one is looking.  Then  well and truly surround and cover with copious woodchips which should be innocculated with a brew of compost and water, a handful to a bucket. After a few weeks introduce a handful of worms.

RIP BoBo Junior,our young  boar who had only fathered one litter. He was killed by a snake last Wednesday.Stew loved this hog who he raised from a weaner. Just our luck we had just despatched the aging BoBo senior, Champion Junior Pig of Woolarama 2007, a few months ago .

For an easy starter worm farm

You'll need:

- 2 polystyrene boxes with lids the same size (broccoli boxes are best)

- A strip of insect screen to fit into the bottom of the boxes

- Shredded newspaper

- A bucket of garden soil,

- Water

- Food scraps

- 1000 composting worms*

* NB: These aren't the same as ordinary earthworms. You will need to buy worms with nicknames like "Tigers", "Reds" and "Blues". They're available from garden centres and worm farmers. Many advertise in the local paper/e bay.

What you need to do

1. Take ONE of your boxes, and make some holes in the lid and in the bottom of the box. This allows oxygen in and also allows extra water and worm wee to drain out. Make your holes evenly spaced. The bigger the container, the more holes you will need. Use a pen or a screwdriver to make the holes.

Spread the insect screen in the bottom, over the holes. This lets the liquid through but stops the worms falling out.

2. Next, fill your container about a quarter  full with shredded newspaper. Dampen your newspaper with water before you add it to the box. All the newspaper should be soaked through but there should not be extra water collecting in the bottom of the bin. Put some garden soil in for initial bedding. Worm casts will gradually be added to the original bedding.

3. It's now time to add some worms to the container. How much you put in depends on the amount of food scraps you plan to compost. 1000 worms are enough to start. They will multiply if you keep them happy.

Place the container (or box) with the worms over the second box, allowing the water and worm wee to drain down into the second box.

4. Next, add some food scraps to the bin. See the chart below for what is good to compost. Make sure you don't overfeed your worms. Start by putting a small amount in one corner underneath some newspaper. See how long it takes your worms to break it down. This should give you an idea of how much your worms can handle at one time. Place your food scraps in a different spot each time.Note worms are surface feeders, just lay the food on top for them. During the cool, dark moist hours they will be feeding there at the surface.

5. Keep an eye on your worms. Make sure that the shredded newspaper does not dry out. Lay a sheet of damp cardboard on top of the food scraps and keep a cover on your box.Again, worms like it better if it's damp and dark and some people house their farms in sheds with no windows for this reason. Over the weeks, the worm wee will collect in the bottom box. You can mix this with water or use neat on your garden. Over the months, a layer of worm poo will build up in the bottom of the top box. One way of removing these castings is to feed the worms on one side of the box only for a few days before  harvest . The worms will nearly all be over in the feeding area when you harvest castings and you wont take too many worms away with the castings. After the raid, spread the remaining  half out flat and start again.

 Vegetable scraps and peelings 

Some people keep an old blender in the kitchen, put fruit and vege waste in there, whizz it up before giving to the worms. This would be helpful in the case of watermelon peel and big stalks and leaves of cauliflower. It’s really spoiling your worms but they will thrive and multiply quickly. Add a bit of water to dryish wastes. Worms like a wet environment but don’t like to swim unless the water is full of oxygen. 

Moisture levels

should be held at 60 to 70 %. An easy way to gauge moisture is to pick up a handful of food without squeezing it. At 70%, drops of water should fall from your hand. It you have to squeeze hard to get a drop of water out, the material is at 50% moisture. Spray evenly with a hose, NOW. Replace cover to keep worms damp and dark.

Serious compost production :

To make large volumes of best quality compost takes larger amounts of waste but the principals are the same.

Follow this recipe :

60% fresh “green” plant material,

30% woody, high carbon or “Brown” material and

10% high nitrogen material.

Examples of Greens:

plant materials harvested green have a high Nitrogen to carbon ratio. This includes coffee beans even though they are brown in colour. It includes fruit and vegetable waste, grass clippings and freshly chipped weeds. These are good bacterial foods.Greens remain "greens" even if they have dried out and turned brown. The simple sugars are still there to feed the bacteria, you just add water and bacteria will breed rapidly. A lot of heat will be generated.

Examples of Browns:

Complex carbohydrate plant material which matured on the plant has a high carbon to nitrogen ratio : hay, straw, chaff, grain hulls, nutshells etc. In this category also are all the wood wastes ( sawdust, shavings, bark, woodchips), paper and cardboard.These very wide C to N ratio materials are the fungal foods.

Examples of high nitrogen material:

Manures and chipped leguminous plants belong here. Worms love a slurry of manure.

A mixture as per above should make up the bulk of your feedstock. In addition, go ahead and add all sorts of household wastes- hair and nail clippings, vacuum cleaner dust ,coffee grounds and tea bags,  crushed egg shells.One thing they really love is soaked paper and cardboard.  It is a very fungal food and so will produce the desirable fungal dominated worm compost.

If you have accidentally added too much high nitrogen stuff, the mixture will heat up and steam your worms. Quickly remove it or add in high carbon things like damp sawdust.

Be careful not to overfeed your worms. Feed just enough that it will all be consumed in 3 days. If there are not enough worms at first to deal with the volumes coming from your house, the waste may get smelly and anaerobic as it sits there. Uneaten food may become a breeding ground for fruit fly . Anaerobic conditions could develop, favoring the likes of e coli. Buy some more worms or reduce food supply till they breed up.

Mature worms who have reached a certain weight are ready to breed and have a saddle around their middle. Each egg capsule ( looks like a grain of wheat in size and shape) can hatch up to 12 baby worms.

A continuous system is a set up in which the bottom inch of cast /bedding material is regularly harvested. This can be achieved by building a “never fill wormery” a la David Murphy in his book ORGANIC GARDENING WITH WORMS.

It is about the size and shape of a wheely bin with a top lid which you lift to deposit kitchen waste, but has 2 inch gap at the bottom which allows one to access the castings.BTW, such a fly proof but ventilated worm bin would be a totally safe way to process human excreta, so lets get building them for every back yard.

Worm egg capsules. 

 The wonderful Nick and Kirsten at Milkwood Permaculture have built both a family sized compost toilet and a system that deals with the wastes of big crowds. See their  wheelie-bin compost toilet system here.

Back to commercial wormfarms, many have a big worm bin on legs with mechanised cutter bar which periodically goes along underneath , slicing off the bottom inch of castings allowing them to fall through the mesh bottom of the bin for harvesting by machine.

Worm casts are miraculous and are the ideal starting material for a brilliant compost tea. Thanks worms!