In response to the posing threat of chemically produced crops using synthetic fertilizers for human consumption, organic farming using earthworms in composting has resorted. This study is carried out to determine the effects of locally available substrates on the reproduction rate of earthworms and the NPK content of its castings. It was laid out with seven treatments replicated three times in Completely Randomized Design. Treatments used were 75% goat manure plus 25% of various substrates such as banana leaves, grass clippings, rice straw, legume leaves, cassava leaves, banana bracts, and sawdust. They were shredded, partially decomposed, transferred to the beds for earthworm feeding, and harvested after 45 days. The castings were collected, separated from the biomass, weighed, and were sent for laboratory analysis. The highest reproduction rate of earthworm biomass was in Treatments with sawdust and legume leaves. Treatments with banana bracts and legume leaves had significantly higher Nitrogen and Phosphorous. Higher Potassium content was noted in treatments with sawdust and legume leaves. It is recommended to use 75% goat manure and a combination of legumes leaves and sawdust for a higher rate of reproduction of vermi biomass and higher contents of Nitrogen, Phosphorous, and Potassium (NPK) in the castings.