Temperature monitoring

Two weeks ago, I set out three Kestrel DROP dataloggers in areas growing vegetables on campus. They record temperature, relative humidity, heat index, and dew point at regular intervals. They are currently set to record every 10 minutes, so they have already collected more than 20,000 data points between them!

Free Android or iOS apps give any bluetooth-enabled phone access to the data stored on the devices. The phone needs to be held within three meters of the device to download its data.

Two of the dataloggers are in areas of the campus terrace garden growing cucumbers. One was in a bed with a row cover, and the other is just outside the bed. I removed the row cover on June 6th.

The third datalogger is in our transplant production unit, in KPU's underground parking area.

Here are the temperature readings recorded so far:

Temperature readings from Kestral DROP dataloggers placed in the
transplant production unit below campus (Transplants) and in the campus terrace gardens,
with and without row covers (Cover and No cover, respectively), over the past two weeks.

The outdoor dataloggers have recorded some very high temperatures over the past two weeks. On sunny afternoons, the temperature under the row cover peaked in the high 40s or low 50s, about 10 degrees higher than the temperature without a row cover. The difference between the two outdoor units disappeared on June 6th, when I removed the row cover. Nighttime low temperatures were about the same with, or without, a row cover.

The heat-loving crops growing under the row covers included cucumber, eggplant, sweet sorghum, and peppers. All appeared to thrive despite the high daytime temperatures. I removed the row covers to give pollinators access to the plants once the eggplants and peppers started to flower.

Eggplant flowering

The daily temperature flux was much lower in our transplant production unit than outdoors. Daytime temperatures have been about 6 degrees higher than nighttime temperatures. Temperature tends to rise over the course of each day, and fall over the course of each night. Our transplant production unit is never exposed to sunlight, but includes electric heat mats and fluorescent grow lights on timers set to turn off each night and on each day.

The average temperature in the transplant production unit has increased over the past two weeks, perhaps suggesting that the parking garage has been warming over spring. The parking garage is not climate controlled.