Intensive peat mining in Chile and worldwide produces a significant increase in production costs and less market availability. Alternative systems to promote peat mining sustainability are an immediate necessity. A viable alternative for replacing peat in tomato transplant production is to use worm castings or vermicompost. Vermicomposting is a biological process that relies on the action of earthworms (Eisenia sp.) to stabilize waste organic materials. The objective of this study was to evaluate the use of Ecobol-S® worm castings as a replacement for peat in tomato transplant production. Three experiments were designed using a randomized complete-block design containing two factors (planting date and worm casting rate). Tomatoes were seeded in a growth chamber using five growth media made up of the different ratios of worm castings, peat, and rice hulls [0:70:30 (control) 18:52:30; 35:35:30; 52:18:30; and 70:0:30], respectively. It was determined that Ecobol-S® worm castings have an adequate C:N and particle size for tomato transplant production. However, limitations were observed due to its high EC and low C content. During early fall, with high temperature in the growth chamber, it is not recommended to use worm castings in transplant production due to nutrient leaching caused by frequent irrigation. In mid-fall, it is recommended to use a rate of 35% worm castings, while in early winter it is recommended to use a rate of 52% to obtain strong and healthy transplants. Therefore, worm castings can be used as a viable alternative in the tomato transplant industry in Chile and possibly worldwide.