vermiculture and worm castings in the words of Don Dillon

I asked Don if he could write a few words (uh, this is a lot more than a few Don!)about vermicomposting because 1- he's really good at it and 2 - folks ask us about composting and in regards to making compost we are mediocre at best(don't mention to Adam I used the word mediocre!)so it's better to have the words of someone with more expertise to answer those questions and 3 - it's interesting!
so with much adieu

Don's words on vermicomposting

Worm Castings
Worm castings are the end product after worms have digested the remnants of decaying plant matter, animal manure or other organic materials such as leaves, twigs, vegetable scraps, etc. Worm castings are rich in water-soluble plant nutrients and contain an abundance of organic humus. Humus increases the soil's ability to store these nutrients and prevents them from leaching away by rain or irrigation. A worm eats organic material that is being broken down by bacteria, fungus, and other microbial life in the soil. A worm’s digestive tract is also filled with these beneficial microbes that break down the organic material to release nutrients for the worm to absorb as food. These microbes multiply in the worm’s digestive tract and are expelled along with excess undigested organic material as ‘castings’ from the worms. In fact, there are so many more microbes leaving the worm then are ingested, the output castings become biologically dense with this beneficial biology. This living biology is very valuable to the plants ability to absorb nutrients and the overall health of the soil.

Plants and Living Soil
The maintenance of a living soil environment is very important for the health of a plant. When there is sufficient beneficial microbial life in a healthy soil, a symbiotic relationship is developed between the plant and the soil. The bacteria provide nutrition for the plants by breaking down the minerals and elements locked in the soil, making them readily available for the plant to absorb. The plant roots in turn release a variety of compounds to encourage and regulate the beneficial microbial community in their immediate vicinity. By creating an area that is conducive to the beneficial bacteria around their root zone, the bacteria will thrive and continue to supply the necessary nutrition for the plant.

Using VermiCompost
The worm castings are integrated into the plant/soil environment by many methods; mixed into potting mix, directly into the soil as a soil amendment, top dressing an established plant, or steep as a tea and applied as a foliar spray or fed to the root zone. Adding directly to the soil or plant creates a long term benefit by adding the living microbes into the soil where they will continue to reproduce and increase the fertility of the soil for the plants. A compost tea has the added benefit of applying the beneficial microbes and nutrients directly onto the plant leaves and stems when applied as a foliar spray. Spraying has the added benefit of directly feeding the plant, and allows the beneficial bacteria and microbes to establish residency on the plant surface. Establishing this residency removes available surface area for pests and harmful microbial entities to attack. The tea can also be used as a soil drench, which saturates the plant root zone with needed nutrients and beneficial bacterial immediately.

Compost Tea
“Passive" compost tea is prepared by steeping worm castings in a bucket of water for 1 or more days to extract the populations of beneficial bacteria and microbes. The water is then strained and applied to the plant leaves as a foliar spray, or fed directly to the roots. Since the compost tea will not harm or burn the plant, it can be freely added as often as desired. Many irrigation systems allow for direct injection directly into the main line so it is dispensed throughout the entire system.
“Aerated Compost tea” is an oxygenated tea brewed with a food source— such as molasses, kelp, rock dust, humic-fulvic acids. The castings are added to water, the food source is added, and the tea is kept highly oxygenated by use of air pumps or bubblers. By adding the food and oxygen, the microbial life multiplies exponentially (often > 10,000 times the original number of microorganisms) over a 12 to 24 hours period. Application of Aerated tea is the same as for Passive tea, but applies much more of the beneficial microbes then the passive method. Often, very specific recipes are use to target which bacteria or fungus is desired to grow in the tea to be used for specific applications such as fruiting trees, pest resistance, flowers, etc.

Raising worms and harvesting castings
At Eli’s Greens Nursery in Farmville, Va. We raise worms in raised beds, very much like a garden raised bed. We currently have three worm bins that are 10’ long by 3’ wide by 3’ tall, and have plans for several more in the fall. The worms are composting worms known as ‘Red Wigglers’. Compost worms differ from Night crawlers because they live only in the top, organically rich compost of the soil layer. Night crawlers are earth digging worms that will maintain a tunnel going down into the earth sometimes 6 to 8 feet in depth.



A worm bed is composed of organic material, with a usual carbon to nitrogen mixture of greater than 40 to 1. Carbons are usually things like dried leaves, sawdust, straw, and paper or cardboard. Nitrogen rich material is stuff like green leaves, vegetables, and fresh grass clippings. Since the worms eat decomposing organic material, and everything in the worm bed is organic material, everything is eventually is broken down by the bacteria and microbes and fungus and all the other critters that are part of the decomposition cycle, and is consumed by the worms and converted into castings.
To harvest the castings, we have what is called a rotary sifter. It uses a 1/4 inch mesh screen to separate the finished casting from the worms and larger unfinished pieces. After separation, the worms and big pieces go back into the worm bin, with some new bedding and food to start the process all over again.
It’s been said that given perfect conditions, a worm can eat its own body weight in food every day and the population will double every 3 months. Unfortunately, I can’t validate the accuracy of this because doing a census count on worms is impossible, but I will say that they do seem to eat a lot of organic material and produce a lot of grade AAA castings.