Earthworms
There are two types of castings. The first, vermicompost, also sometimes called `Live Castings’, will contain capsules and even immature worms. It can be used for inoculating market gardens, pastures and garden soils with worms. Vermicompost will also contain a proportion of uneaten worm food and, for this reason, cannot be referred to simply as castings.
The second is Vermicast. It consists of castings which have been thoroughly eaten over by the worms so that all the food has been consumed and converted to casts, all the capsules have hatched, and the young worms have left.
Benefits of Worm Castings
Here are some brief results of a trial comparing growth rates of plants in soil and/or castings.
This clearly demonstrates the improvement in plant growth if castings are used instead of, or even in conjunction with, normal soil. The fact that the castings were gathered from the soil surface and not derived from an exceptionally rich foodstuff such as animal manures is an important consideration.
Apart from the substantial weight increase of the plant itself when grown in pure castings, the weight of the root systems is particularly significant, showing the effect castings have on plant health.
Why should castings be such a superior growth medium?
The answer is that in castings more nutrition is available to the plants.
Personal advice from Dr Clive Edwards, Department of Entomology, Ohio State University, is that vermicast also contains plant growth hormones, produced by the bacteria from the worms.
Organic Growers
There is an increasing awareness in our community of the superior health and dietary value of organically produced foodstuffs. Organic market gardeners should plant their vegetables in vermicast and they would do so if there were enough castings available.
Worm Castings
Nurseries
Just give a second’s thought to the number of plant nurseries near you. They all use large quantities of germinating and potting mixes, most of which they make themselves. Once the outstanding benefits of vermicast are demonstrated, they should be eager to change.
Seed -Free Castings
If the seed isn’t in the feed in the first place, it can’t be in the castings. You can achieve this by using as a food source manures from animals which have been fed on manufactured foodstuff in which all the grains have been crushed. Pig manure is an example of this. Another infallible way to produce a seed-free vermicast is to feed a selected bed with bran or pollard. In this case you must feed with a light sprinkle on top only, never mix it in, and feed two or three times each day. It will be more expensive to produce if you compare the cost of manure as a feed, but you will recoup your costs many times over.
If you decide to use manure, you must fully compost it before feeding so that the seeds are destroyed by the heat.
More expensive than any of the above methods is pasteurising the vermicast after it has been produced. This involves heating the castings to 60°C and holding the temperature for thirty minutes, The process destroys not only :cods, but also worms and capsules. However, it does not harm the bacteria. Curators of bowling greens and growers of instant turf insist on pasteurised vermicast.
Bowling clubs do not want the risk of any little mounds of castings being deposited on the greens overnight, neither do they or turf growers want any grass appearing other than the one they planted. However, bowling greens conditioned with treated castings have a long life before it becomes necessary for them to be torn up and relaid, so that the economics of using vermicast are attractive.
