Evaluation of Vegetable Production on Extensive Green Roofs

摘要

Rooftop vegetable gardening is a production system in urban agriculture based on green roof technology. To broaden the scope of this practice, the use of relatively shallow substrate depths must be explored, since most existing flat roofs are unable to support much added weight. 'Ihree growing systems—a green roof, raised green roof platforms, and in-ground—were evaluated for vegetable and herb production over three growing seasons (2009-2011). Tomatoes fSolanum lycopersicurrO, green beans f Phaseolus vulgaris), cucumbers fCucumis sativus), peppers f Capsicum annuurrU, basil fOcimum basilicurrO, and chives f Allium schoenoprasurnj were studied because of their common use in home gardens. All plants, except pepper, survived and produced biomass inall growing systems and yielded crops large enough for analysis in 2009 and 2010. Overall, yields and basil biomass were higher and of better quality in-ground during 2009, the only year irrigation was applied, and similar on the roof and platforms. Variability in success was partially due to annual weather variation with the greatest impact on cucumber. Yields of chive, a perennial crop, were not affected by growing system after the first year. Results suggest that, with proper management, vegetable and herb production in an extensive green roof system is possible and productive.