(back to main)

Benefits to Soil

    Vermicompost (i.e. worm castings and worm tea), the product of vermiculture, is a great additive to soil.  It helps to increase soil structure while adding nutrients.

    Organic matter added to soil help to give the soil better structure (binding of soil particles together).  Structure increases the aeration of soil, which facilitates oxygen reaching plant roots.  This helps plants (crops) to have better growth rates.  Organic matter also increases the cation exchange capacity of soil (CEC).  This helps to hold cations in the soil where they are available for plant uptake.  Soils that have low CEC values lose many nutrients through the leaching process.

    Vermicompost is also nutrient rich.  It contains: nitrogen, phosphorous, potassium, calcium, sodium, magnesium, iron, zinc, manganese, copper, boron, and aluminum.  The most important of these being the nitrogen, phosphorous, and potassium that they add to the soil.  Many cropping areas are deficient in at least one of these nutrients.  By adding the vermicompost to a crop area, money that would have been spent on fertilizer may be saved.

Vermicomposting and Traditional Composting

    Traditional composting involves only the action of bacteria and fungus to break down organic material.  This process has been going on anywhere where there is organic material, heat, and moisture.  Most people commonly know these as compost piles for grass clippings and other yard materials.  The traditional pile does not decompose material as quickly as vermicomposting since it lacks the worms.   Worms go through the organic matter much faster than microorganisms.  The worm castings (worm excrete) still has organic matter that can be broken down, and contains microorganisms that are doing just that!

 Both of these systems can be used for the decomposition of organic material, but in vermiculture to end product has more structure due to the casting process of the worms.  The presence of worms also speeds up the process greatly.

           Related Web sites

         Characteristics of garden compost and vermicompost: great table! http://www.cahe.nmsu.edu/pubs/_h/h-164.html

         Fantastic Newsletter resource that deals with vermiculture, composting, soil fertility and related issues of organic waste. http://vermico.com/news.html


Freshly-shredded green waste (yard waste) was composted for 16 weeks using a mechanically-turned windrow system.The rate of organic matter stabilisation was determined by measuring the reduction in the volatile solids content of the waste. Samples of the fresh material were also vermicomposted using Eisenia andrei (Bouche) and rates of growth and reproduction obtained which were comparable to published rates for other wastes. Vermicomposting for 8 weeks produced a material with a significantly lower volatile solids content compared to composting for a similar period (P < 0.01). A combined composting and vermicomposting system was investigated by extracting partially-composted samples from the compost windrow every 2 weeks and feeding these to E. andrei. Growth and reproduction were found to be positivelycorrelated to the volatile solids content of the waste (P <0.01). Vermicomposting partially composted waste (2 weeks), for a further 6 weeks, reduced volatile solids content significantly more than for composting fresh waste for 8 weeks (P <0.001). It is concluded that E. andrei is capable of attaining good rates of growth and reproduction in fresh green waste and that vermicomposting can result in a more stable material (lower volatile solids content) compared to composting. Combining vermicomposting with existing composting operations can also accelerate stabilisation compared to composting alone. The duration of pre-composting will determine the subsequent rate of growth and reproduction of E.andrei. To ensure that the vermicomposting system operates at maximum efficiency, pre-composting should be kept to a minimum, consistent with effective sanitisation of the waste.



Vermiculture Drainage (a.k.a. worm tea)

Vermiculture drainage, or worm tea, is the liquid that flows out of worm bins.  Large amounts of water are used by the worms and the microorganisms in the bins.  The excess liquid must be allowed to drain out through holes in the bottom of the bin.  If the water is not allowed to drain out, conditions could become anaerobic in the bottom of the bin, therefore killing the worms and other beneficial organisms.   This drainage may be collected and used as a fertilizer, as it is loaded with many nutrients.  It contains variable amounts of all the nutrients found in the vermicompost.


"We studied vermicomposting with Eisenia foetida of mustard residues and sugarcane trash mixed with cattle dung in 90-day composting experiment. Vermicomposting resulted in significant reduction in C:N ratio and increase in mineral N, after 90 days of composting, over treatments uninoculated with earthworms. Microbial activity, as measured by dehydrogenase assay, increased up to 60 days and declined on further incubation. There was more total N in the compost prepared by earthworm inoculation. However, the differences were not significant. Total P, K and Cu contents did not differ in compost prepared with earthworm inoculation from the uninoculated treatments".