Many of today’s gardeners want to improve their land’s fertility while also supporting green efforts. One option stands out as a must-have for all our backyard gardens – worm castings. Worms break down all sorts of organic material during their digestion process. This process, known as vermicomposting, yields some of the highest quality soil amendments available and helps create successful, hassle free gardens while conserving resources.
Current research shows extremely complex benefits from the use of worm castings in agriculture. Considered a green technology, vermicomposting is the epitome of the slogan: reduce, reuse, and recycle. Our growing knowledge of these largely unnoticed creatures shows a fascinating connection between worms and the earth’s overall ecosystem health. Their effects on soil biology, nutrient availability, and the complexity of their decomposition of organic materials, are some of the things currently being studied.
Although we are just starting to understand the relationship between earthworms and healthy soils, worms have been fascinating people for millennia. For example, Cleopatra, Queen of the Nile, decreed that worms were sacred and therefore not to be harmed. The Greek philosopher, Aristotle, declared them to be the guts of the soil. The great biologist, Charles Darwin, best known for his theory of evolution, started his scientific work looking at earthworms. He was fascinated by them and utterly convinced that worms were among the unsung heroes within the natural world; and in 1881 he published his lifelong research on earthworms.
Vermicompost (worm castings) stimulate plant growth even when plants are receiving optimal nutrition. Improved seed germination, accelerated growth and development, and increased productivity and yield are all scientifically validated claims. Other benefits, such as disease prevention and the ability to repel pests are also possibilities.
When purchasing worm castings, remember, worms are what they eat, therefore their food source is very important. Choose worm castings produced by worms that have been fed a carbon rich, natural diet including organic material like vegetables and fruits, coffee grounds, seaweed, manures and even corrugated cardboard.
When compared to regular compost, vermicompost stands out as the winner. Higher levels of plant-available nitrogen, phosphorous, potassium, sulfur, and magnesium make vermicompost nutritionally superior. Microbiology is also more complex in vermicompost than standard compost. Why? First, vermicompost is processed at a moderate temperature range that never comes close to the 60° C or higher achieved in standard “hot” (thermogenic) traditional garden compost. This means that worm castings have more microbes meant to live at lower temperatures when compared to those that live in regular compost. Although the process is not entirely understood, it is also clear that worms release more microbes than they ingest, meaning that they are actually facilitating microbial growth during their constant eating. Many composters believe a temperature of 60° C or higher is required to destroy pathogens. However, surprising new research shows that castings produced in a pathogen-rich environment actually contain no pathogens. Dissections show that something happens within the first 5mm of the worm that completely removes pathogens.
Use worm castings as a top dressing or work them it into your medium. The best ratio of castings to mix into your growing medium is about 10%. You can add up to 40%, but using over 40% decreases its value, and can actually slow growth of plants.
According to some estimates there could be more than 1800 species of worms worldwide providing a wide range of choices when looking for worm castings. Many of the worm castings available in retail shops are produced by African nightcrawlers. Another choice is Eisenia fetida, more commonly known as a Red Wiggler, which is indigenous to most parts of the world. This particular worm is extremely tough, adaptable, and able to handle a temperature range from 0-35° C, and the eggs or cocoons can even survive short periods of complete freezing.
Without question, the addition of worm castings can provide gardeners with more vigorous plant growth. For those gardeners up for the challenge, trying small scale worm farming could result in a burst of plant growth while decreasing the waste that leaves your house for the landfill.
– Simon Hart, Greenstar Plant Products
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