The project researched the ecology of vermicomposting manures and the use of vermicompost in horticulture. It was carried out in collaboration with Martins TLC Ltd., a vermicomposting company based in Ceredigion, Wales and the Institute of Biological, Environmental & Rural Sciences, Aberystwyth University. The project was part-funded by the European Social Fund through KESS2. Vermicomposting is a form of composting that uses high densities of particular earthworm species to rapidly decompose, stabilise and release plant nutrients from organic matter. The earthworms promote the action of decomposing bacteria and fungi. The vermicompost researched in this project is used as a constituent of peat-free multipurpose compost as a horticultural growing medium. The horticultural use of vermicompost was investigated by comparing its plant growth performance and key plant nutrient levels against those of other peat-free and peat-based growing media in a greenhouse pot trial. The results showed that all composts performed similarly well and all had high levels of most nutrients. The main conclusion was that this vermicompost would be a suitable alternative to peat-based growing media. The ecology of vermicomposting is key to the efficacy of the vermicompost, and was investigated in a laboratory experiment that explored the effects of the presence or absence of earthworms on the biological, chemical and physical properties of the compost. Additionally, the presence or absence of springtails with and without earthworms was researched in the same experiment. Springtails, which are similar to tiny insects (usually less than 2 mm long) are known to be very important in soil organic matter decomposition and the recycling of plant nutrients. However, their role in vermicomposting has had little attention. This research found that in vermicomposting, springtails can enhance the effects of earthworms in increasing the availability of some key plant nutrients in the vermicompost