Red onions are such a demanding horticultural product that farmers have to grow them intensively. The purpose of this study was to investigate the effects of composting applications of Trichoderma harzianum and his Tithonia diversifolia on shallot growth and production. This research was conducted from October 2021 to January 2022 in Sekkang, Mattiro Sompe, Pinrang, South Sulawesi. The study was conducted by experiment using split plot design in a randomized complete block design which consisted of 2 plot factors such as the Trichoderma harzianum fungus as a main plot with 4 levels of doses, and the sub-plots using Tithonia diversifolia compost with 4 levels of doses. The research was done in three main steps: preparing the media and the material, maintenance and examining the result. The results showed that there was an interaction between the treatment of Trichoderma harzianum 15 g with Tithonia diversifolia compost 3 kg per plot, which gave the best results for plant height (41.78 cm). Then, the application of Trichoderma harzianum 10 g with Tithonia diversifolia compost 3 kg per plot gave the best results on the of tuber fresh weight (89.89 g), tuber dry weight (74.61 g) and production per hectare (18,65 ton).