Differential response of plant species to greenhouse microclimate created by design technology and ambient conditions

Food insecurity amongst First Nation populations living on reserves across Canada is purported to be about 27% of the national average. However, crop production is limited by factors such as climate and soil conditions. A two-year study was carried out to assess production of collard (Brassica oleracea L. var. acephala ‘Champion’), carrot (Daucus carota L. ‘Adelaide’) and tomato (Lycopersicon esculenta L. ‘Beefsteak’) in three separate greenhouses with contrasting design technology. The greenhouses were categorized as: i. high technology (HTG); ii. medium technology (MTG); and iii. low technology (LTG) greenhouses. The MTG and the LTG were basic facilities but the MTG had in-floor heating. The HTG was fully equipped with climate control systems. Mean monthly air temperature was stable at 23±1oC in the HTG but fluctuated in the MTG and the LTG. Air temperature and water loss were highest in the MTG. Vapor pressure deficit and daily light integral followed the trends, LTG>MTG>HTG>ambient; and ambient>MTG>HTG>LTG, respectively. Growth rate of collard plants was equally high in the MTG and the LTG as compared to the HTG. Comparatively, growth and yield of carrot plants were highest in the HTG. Conditions in the HTG and the MTG favored growth and yield of the tomato plants. Thus, the different greenhouse design technology created different microclimates, which differentially affected growth and yield performances of the different vegetable species. Future work should consider economic benefits of greenhouse technology and production management for northern and remote communities.