Mushroom production in India is typically restricted to cooler months due to the difficulty of maintaining stable environmental conditions in open or low-cost setups. We developed and field-tested Mushroom Kothi, an IoT-enabled chamber designed to deliver real-time climate control and monitoring for smallholder mushroom farmers. Across three agro-climatic sites and two seasons, replicated trials compared Oyster mushroom (Pleurotus ostreatus) production in Mushroom Kothi versus conventional farmer practice. Continuous sensor logging of temperature, relative humidity, CO₂, light, and substrate moisture enabled automated misting and ventilation adjustments through a cloud-connected ESP32-based system. Preliminary results indicate yield gains of 15–25%, reduction in water use by 30–35%, and improved uniformity of fruit body size. Time-to-harvest was shortened by 1–3 days, while the productive window extended beyond conventional seasonal limits. Statistical analyses (two-way ANOVA, Tukey HSD) confirmed significant treatment effects (p < 0.05) across sites. In addition to production benefits, the system achieved high reliability with >95% data transmission success and reduced manual interventions, demonstrating ease of adoption in low-resource settings. By combining continuous digital monitoring with automated environmental control, Mushroom Kothi provides an affordable precision agriculture tool that enhances productivity, reduces input waste, and improves the resilience of mushroom farming. Future work will integrate predictive analytics to further support farmer decision-making.