About a month ago I got in contact with one of my graduates from the Horticultural Program at Malaspina. I had heard that she had continued to work at her business of worm farming, and decided that it was time that I investigated a bit further. I was invited over to see her worm farm in her garage, and purchased a small worm farm of my own. The kit was very cleverly made from two Rubbermaid bins, and included some coconut fibre, newspaper shredding, a plastic screen, a hand sized gardening fork and a pound of worms. I have to admit I was apprehensive, but a month later I am totally delighted with my little organic fertilizer factory. The worms have worked silently and diligently away in their home under a shelf in my kitchen. With very little care and attention they have turned the pulp from my juicer into a wonderful granular like fertilizer high in nutrients and microorganisms. As I researched the benefits of worm castings I was amazed at what this granular, soil like substance can do for my plants.
First of all, worm castings are absolutely jam packed with plant nutrients in a readily absorbable form. To make things even better they tend to be in a form that does not easily wash away with excessive rain or irrigation as they tend to get attached to soil particles by the microorganisms present in the castings. This allows nutrients to be held in the soil and taken up as the plants need them, thereby creating an ideal situation for the plants. Some of the organisms present in worm castings attach to the roots of the plant and assist it in breaking down any nutrients available in the soil. I have witnessed many times throughout my career how plants that were stressed by nutrient imbalances or shortages were the first plants that were attacked by insects and diseases. One report I read reported how Nitrogen can actually be released in the soil by the predation of bacteria by the type of soil microorganisms that are present in castings. No need for 20-20-20.
Another benefit of worm castings is their ability to reduce pest and disease problems. Although disease organisms are almost always present in the soil, it is only when they get out of balance that they will spread to the roots of our plants. The microorganisms that are present in worm castings are extremely diverse and as they colonize the soil ecosystem they tend to balance the populations of microscopic organisms that exist there. With a diverse population of organisms these soil borne diseases can be kept in check as they become food for many of the beneficial microbes that are introduced. Some studies have shown that worm castings also help control insect infestations due to the presence of chitinase, which can break down the exoskeleton of some of our common pest insects.
Worm castings can be applied to the soil as an amendment. For containers and houseplants add worm castings to between 10 and 20% of soil volume. In the garden you can top-dress perennials with about a half cup of castings and lightly scratch them into the surface of the soil. Lawns are very hungry feeders, and will appreciate 4 litres per 100 square feet of lawn. You can also make a tea with the castings and apply it as a foliar feed for plants at the rate of 1 part tea to 5 parts water. This will protect, enhance and restore the microbial life that is present on the surface of the leaf that serves to protect against disease and also provide a quick, easily absorbable form of nutrients to the plant. The tea is especially good for cuttings and young transplants since nutrients cannot be easily absorbed from the soil after the cuttings is freshly removed from the plant and when the number of young roots is very small.
I intend to continue to raise more worms and as they have families and multiply I plant to provide homes for more and more of these wonderful creatures who so willingly turn waste into high quality fertilizer plus. The care and feeding of these creatures is truly minimal. I feed my pound of worms in their small bin (about 1by 2 feet) about 2 cups of food about twice, sometimes three times a week. I have been advised not to over-feed them as that is one of the things that can create problems in a worm bin. I know the worms are hungry when the amount of shredded paper tends to rapidly decrease, a sign that the worms are hungry. I add ground up food from my juicer, but you can also run some kitchen scraps through the blender. The ground food has more surface area that can be exposed to air, needed by organisms that will start to break food down. The worms in the bin appreciate this minor preparation of their food. When I add food I add it in a different corner of the bin every time. I place a fork in the bin to indicate where I have last placed food. I found that they really like ground apples and carrots, and adore leftover oatmeal and brown rice. I was warned that they do not like onions at all, and I have found they do not like citrus as much as other foods. I have also found that they are far more active (and therefore eat more) in a warm room then in a cool one, and that is what prompted me to keep them in the kitchen. There has been no odour at all from my bin, either sitting there with the lid on or even when I open it to check on my kitchen pets or to feed them. I hope that over time I will have enough worms to feed all my kitchen scraps to and will be producing mounds of worm gold for my garden. For those of you who are not interested in keeping these pets around I would advise trying a purchase of some ready -made castings and giving them a try. I am sure you will notice healthier, happier plants and will come back for more. Who knows, you may even decide you do have room for a little organic fertilizer manufacturing plant in your home after all.