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Worm Farming & Cultivation For Fishing

Words and Images: Dr. Gareth Coombs

During my formative years as a young fisherman, we always had to dig worms for a day’s fishing if we wanted a supply of “erties” to catch yellowish, barbel or bluegill. Many afternoons after school were spent with digging fork in hand and filling a bucket with worms. In one unfortunate incident, one of my friends in fact put one of the digging fork’s teeth right through his foot when he was not paying attention!

Finding mating pairs of earthworms is a good sign of suitable soil conditions.

Worm farming has become increasingly popular owing to increasing environmentally friendly household practices where worms are used to process much of our kitchen waste or in large schemes where they are used to produce a very rich fertilizer. When used for household purposes, they can certainly be outstanding.  Of course, as an avid fisherman, the thought of having my own readily available worm supply far exceeds any thoughts about their use for kitchen waste, but that’s just me.

The most commonly available and easy to cultivate worm is the red wriggler or Kariba worm that is  for sale in just about all angling stores. These worms are easy to keep and don’t have highly specialized substrate requirements. They breed and multiply at an incredible rate during the warmer months of the year, and will slow down dramatically during winter if you don’t artificially heat them. Personally I don’t bother to heat my worms during winter as you don’t use worm baits in freshwater that often during the colder months, thus the supply you have should be enough. Red wrigglers can be bought from different stores or can even be ordered online. There is also an increasing number of companies that sell complete worm farming kits (online) which are good options if you don’t have the time to build a worm farm yourself. Other worm types certainly have the potential to be farmed, but they seem to have very specific soil condition requirements such as ph, nutrients, temperature and water content. This is certainly natural if you think of how different species are likely to co-exist by separating their niches.

The availability of a great array of modern plastic containers that can be used to house worms, coupled with the relative simplicity of constructing a functional worm farm, makes establishing your own worm farm dead easy. Plastic plumbing supplies which may be used to construct a drain are also cheap to come by.

A large black container bin such as the Addis Roughtote provide excellent containers for small worm farms.

 To construct the most basic worm farm you will need nothing more than a large plastic bin (those made by Addis, marketed under the name RoughTote®), about 5kg of compost mixed 1:1 with potting soil and a start-up colony of about 50 to 100 worms.  It is best to place the worm box on top of a slightly larger container which can function as a drainage pan.

Keeping the moisture content of the soil at the correct level is extremely important. This is related to the fundamental biology of the earthworm – they don’t have lungs and gain all their oxygen through diffusion from the air contained in the small pores and crevices (known as interstitial spaces) within the soil. If the soil is too dry, the worms dry out and struggle to obtain oxygen; if the soil is too wet, the worms effectively drown due to there not being enough dissolved oxygen in the water surrounding them. Fortunately, maintaining the correct soil water content is not that difficult. Open the container at least every two days, and see if the soil is too dry. If you have drainage holes, it is very unlikely that you’re soil will become too wet. If you stick your finger into the soil and it is covered by a thin layer of moisture, when you draw it out, that is about the right moisture content.

Feeding your worm colony is relatively easy and the amount of food that you introduce depends on the colony size and also the substrate. Substrates such as cow and horse manure are already a good source of food for worms as they contain a lot of nutrient-rich decaying plant material.  If you live in town and access to horse or cow manure is a problem then it takes a while for the soil to become relatively mature and form fibrous humus-like structure. These non-mature and “fresh” substrates need to be fed every other day and the soil turned over thoroughly once a week. Within a month or so you should start to have a soil which is organically more active with bacteria (harmless to you!) that assists in the breakdown process. You will feel this in the soil texture when it changes from being firm and grainy to a fluffy, looser texture. Once your soil is mature, your worms will multiply fast and grow relatively rapidly.

An old metal bath filled with horse manure forms an ideal container to cultivate earthworms. The advantage of such tough containers are that you can easily dig old garden and kitchen vegetable scraps into the substrate using a metal spade.

Under the right soil and temperature conditions a colony of red wrigglers can multiply impressively fast. If you regularly dig through the soil and inspect clumps of decaying vegetable material you’ll see hordes of newly emerged small worms crawling through the substrate. One also often finds mating pairs of earthworms, where the two saddles are wrapped together which is a good sign that you are maintaining the correct breeding conditions for your worms.

It is important to note that a worm farm should not smell badly or of rotting material, else something is wrong.  Really potent smells are typically produced by meat offal, which should not be in your worm box. The decomposition of meat results in the release of noxious and fowl smelling gasses, which gives it that sulphurous putrid smell. You should be able to stick your hand in the soil, grab a small amount of earth and it should have nothing but a humic type of smell.

Once you have established a worm colony, harvesting them is easy. To look for worms you can turn the soil either with a small spade or by hand to collect them. When collecting worms for fishing, it’s not crucial to worry about the size of the worms as they mature fast enough to replenish their numbers within a short period. If you use earthworms as groundfeed for tilapia or incorporate chopped earthworms into groundbait for carp and yellowfish, its best to expand the size of your colony to be able to harvest large amounts regularly.

A healthy quantity of earthworms successfully cultured in horse manure.