Instruments for monitoring the greenhouse aerial environment, part 2 of 3

Aerial environment characteristics are quantified with instruments that provide numbers. With these numbers we can compare the environment under investigation with a predetermined standard and then seek improvement in greenhouse conditions. We can also evaluate changes in the environment over time. For example, a simple thermometer tells us that the air temperature in a greenhouse is 85ºF, yet we determined the optimum plant temperature is around 75ºF or colder. Our goal would be to lower the temperature or compensate for the heat stress in other ways. This publication examines portable, hand-held, field quality instruments commonly used to diagnose greenhouses and other plant production environments (propagation rooms, growth chambers, etc.). Limited discussion is provided about some permanently installed greenhouse sensors and portable dataloggers. It does not discuss ventilation system controls or instruments used to obtain scientific data. A table of instrument costs and suppliers is provided. Hand-held instruments can offer sophisticated computer interface capabilities, datalogging, and simple data evaluations such as maximum, minimum, and average readings. Expect to pay more for these capabilities and instruments with high accuracy. One responsibility of instrument use is the proper maintenance of instrument calibration.Bulletin E27