CO₂ enrichment is a strategy commonly employed by indoor/vertical farms to improve crop yields. Artificially elevating the CO₂ concentration within an enclosed growth space results in improved photosynthetic efficiency, and therefore improved crop growth rates and flavor profiles. Alcohol fermentation provides a steady stream of CO₂ that is emitted to the atmosphere as a by-product. To evaluate the feasibility of using fermentation off-gas as a source for indoor carbon dioxide (CO₂) enrichment, spinach plants were randomly assigned to 2 growth chambers. The control chamber was maintained under ambient CO₂ concentrations, while the treatment chamber was piped onto a flow control system capable of delivering CO₂ from a beer fermentation vessel to the growth chamber to maintain CO₂ levels at a setpoint of 1200 parts-per-million (ppm). CO₂ flow was diverted to the growth chamber when levels were below 1200 ppm, and to an external exhaust when chamber levels were above 1200 ppm, with the flow control device measuring internal CO₂ concentrations and responding accordingly every 6 seconds. A standardized batch of beer was used to replenish the fermentation source to maintain continuous fermentation and CO₂ off-gas production. The CO₂ flow control device successfully maintained a strong oscillation of CO₂ around the 1200 ppm setpoint within the treatment growth chamber for the duration of the 50-day growth period. Spinach plants grown in the treatment chamber produced significantly more fresh biomass (5.456 g vs. 2.888 g, P < 0.0001), dry biomass (0.5711 g vs. 0.271 g, P = 0.0002), and significantly longer leaf lengths (231.0 mm vs. 159.9 mm, P < 0.0001) than their control chamber counterparts, respectively. This represents an 89% increase in fresh spinach crop yield within a controlled indoor growth environment.

The dataset wass collected by harvesting plants and evaluating them for fresh weight, dry weight, and longest leaf+stem