Microclimatic Conditions of an Agricultural Array on a 5th Floor Façade in Downtown Portland, OR

Building integrated agriculture (BIA) includes the practice of locating growing systems on and in mixed-used buildings to exploit synergies between the building environment and food production. Despite increased interest in BIA, few published reports of basic BIA-related data exist. Currently, very little is known about how BIA affects or is affected by urban microclimates. We documented fluctuations in soil moisture and temperature, as well as ambient air temperature and relative humidity, in an outdoor agricultural array on the 5th floor of the PAE Living Building in downtown Portland, OR. Air temperatures fluctuated more than soil temperature, and were highest on the south-facing aspect of the building. Soil moisture varied among window bays, with drought tolerant plants faring better. Somewhat unexpectedly, given the 5th floor location of the array, insect pest damage was observed, and crops dependent on insect pollination set fruit. This short term study suggests that building integrated agriculture arrays may be robust to large fluctuations in ambient relative and air temperature, perhaps because of shading, or the thermal mass of the building. This bodes well for successful scaling of BIAs, amidst a changing and highly variable climate. Additionally, the presence of insects in the agricultural array despite the urban downtown location and elevation above street level could bode well for agroecology in urban BIA.