DOI: 10.5061/dryad.15dv41p6f
title: Controlled carbon dioxide enrichment using beer fermentation off-gas results in 89% spinach yield increase

description: 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 &lt;
 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 &lt; 0.0001) than their
 control chamber counterparts, respectively. This represents an 89%
 increase in fresh spinach crop yield within a controlled indoor growth
 environment.
description: The dataset wass collected by harvesting plants and evaluating
 them for fresh weight, dry weight, and longest leaf+stem
description: # Controlled Carbon Dioxide Enrichment Using Beer Fermentation Off-Gas
 Results in 89% Spinach Yield Increase
 [https://doi.org/10.5061/dryad.15dv41p6f](https://doi.org/10.5061/dryad.15dv41p6f) ## Description of the data and file structure 8 plants were grown in each of 2 chambers (Control, and Treatment). The "Treatment" chamber was CO2 enriched using fermentation off-gas. One of the 8 control chamber plants was stunted, and therefore removed from analysis to prevent it from positively biasing the effect of the treatment relative to the control. The removed plant is identified in the data file. Total above ground biomass was harvested and weighed. The longest stem/leaf length was then taken, and finally, plants were dried and weighed for dry weight.  ### Files and variables #### File: Raw\_Data.csv **Description:** Raw fresh weight, dry weight, and stem/leaf length data ##### Variables * Control: 8 plants (7 used for analysis) grown under ambient air conditions * Treatment: 8 plants grown under CO2 enrichment at 1200 ppm using fermentation off-gas