Making your own vermiculture or ‘worm farm’ is not very difficult (see the many instructions on internet). Maybe the most difficult bit here is acquiring the right type of worms. The ‘red wiggler’ which you can order by mail in Australia, US or the UK is not available through the mail man in the Netherlands. The manure heap – a left over of last year – in the corner of our allotment garden proved the solution. The red wiggler likes manure. We dug in and ‘harvested’ around a hundred last year september and again a hundred in the spring. By now we have a healthy population which reproduces and soon we might need to expand our farm or donate worms to a new farm….
The ‘farm’ consists of three plastic storage boxes which are piled on top of each other with one of the lids on the top box. If put on top of each other, each box leaves some space at the bottom of the other box, about one sixth of the whole volume. The lowest box stays as it is, in here the liquid which can be used as fertilizer will drip. From the two other boxes we removed the bottom and replaced it with a plastic grid (for which we used a painting grid on which you roll off the excess wall paint). The grid allows the worms to migrate to the next box once they are ‘done’ with the food scrapes in their current box. The grid bottomed box receives a bedding of torn and humid newspaper and can then be filled with food scrapes.
All vegetable matter apart from union and citrus scrapes can be put in, the latter make the box matter too acidic. However, it is important not to over-feed the worms with too much organic matter. The classical mistake each manual will tell you and indeed, we did so too. It takes a while before they are really eating well. The balance comes quite close and it took us a while to get into a good feeding rhythm. Other preconditions for a healthy worm farm are, some very small air holes, the right humidity, moderate temperatures (the box not in the full sun) and regular attendance of the owner.
Harvesting the soil is pretty easy with the two-story system. You always put food scrapes in only one box, the top one. Once the worms have eaten their way through the scrapes in the lower box they migrate upwards through the grid to the new box where the organic matter is already rotting, something they like rather than averse. When the top box is covered with a wet newspaper and the lid, the farm does not smell.
Of course, if you have a big garden at your disposal, a compost heap will do. There is no need for a vermiculture system if you have space, although the fertility of the soil increases through the worm castings (see the Growing Power example of Will Allen). For small-housed urbanites, however, the worm farm is a useful part in the household nutrient cycle.