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Most beds in our shade-houses have reasonable to good populations of compost worms. These worms break down dead organic matter, like dropped leaves and roots left after harvesting, into their component parts so that other plants can use these again. The micro-organisms in their gut also bind raw minerals from the soil to certain organic acids or sugars in a process called chelation. Plants can easily absorb these chelated forms of minerals. They (and we) cannot absorb minerals in their raw forms, or not as easily. There is evidence that naturally formed chelated compounds are more effective than the ones we can buy. And offcourse they are much cheaper.
Worm castings (or cast) are thus a valuable source of plant-available nutrients including the all-important minerals; provided the latter are present in the soil. As most Australian soils are low in minerals, make sure to add them. In addition, the cast contain enzymes that can protect crops against some diseases. Cast is free from harmful micro-organism and rich in beneficial ones. The latter increase the humic components of the soil, which leads to faster wicking, better water holding capacity and higher nutrient storage of the soil.
The tunnelling activities of the worms help to increase the amounts of air and water that get into the soil. Good worm populations, good soil structure, good natural plant nutrition and a healthy micro-flora go together to give us nutritious vegetables and crops.
There are some 2000+ species of worms in the world, and they all do different things.
Photo 1 shows some that are best for our gardens. The large ones on the left are ‘Gardeners Friends’, they excel in building soil-structure. In the heap on the right are four composting worms: ‘Reds’, ‘Tigers’, ‘Indian Blues’ and ‘African Night Crawlers’.
Composting worms will make compost out of anything that was once alive and re-cycle it.
Photo 1: worms change Photo 2: loose soil into: Photo 3: a structured soil.
You can get all five species in one package, plus a variety of in-bed worm-feeders, from WWW.KOOKABURRAWORMFARMS.COM.AU. The site also gives information about them.
The combined action of worms and the soil micro-flora has changed our loose mixtures of clay, sand, loam and mineral supplements into very well-structured soils. This has large and small holes in it from worms and plant roots, while fungi threads can be seen when it is freshly dug. When we need a finer tilth for planting, it can easily be fragmented again.
(The lump of soil in photo 3 was from a bed where we replaced the original chicken wire with fencing cloth. The lump was dry when we put it into water. The water soaked up to the top in about 10-15 minutes. After four weeks, the lump fell apart into three bits. After six weeks it was a fine tilth of crumbles.)
The worms are introduced and continuously fed through in-bed worm-feeders. Everything vegetative goes into those. The worms also feed on the mulch on the surface of the bed and any left-behind roots in the soil. They do not eat living plant materials such as roots. There are many types of worm-feeders, but they all need to be rat-proof.
We use Yates Tuscan flower pots – the size with a 30 cm bottom diameter –with matching saucer (photo 4, the two pots on the left).
Photo 4 Photo 5
For our purpose, we cut the bottom off the pot (photo 4 the third pot). We then turn the pot upside down and use the saucer as a lid (the pot on the right). It fits snugly.
At first we placed the pot above the soil (photo 5, the left pot). We dug the rim about 3 cm into the soil. It worked well in the cooler part of the year but the pot became hot and dry in mid-summer, as we did not water the worm-feeders often enough. We designed our system so we don’t have to be in the garden every day; just often enough to keep sufficient water in the reservoir. That was not often enough to keep the worm-feeders moist. The result was no worms and no composting. We now dig the pots deep into the bed (photo 5 the pot on the right). The bottom layer is in permanently moist soil where it does not get hot. Over time the worms fill up the pots with cast, but that is easily dug out and used elsewhere.
In a new bed we place a layer of organic material at the bottom: bagasse, hay, grass or crop residues, to give the worms a good start. These tie up nitrogen initially, so we compensate for that with a dose of a good nitrogen-containing supplement and leave it settle for while.
Other people use different designs, both above and in-ground. They can all work as long as they fit in with your gardening habits. After all, you are the main part of the system.
Photo 6 A bench-top Photo 7: The little Rotter Photo 8: A Garden bed worm-farm. rubbish bin with holes.
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