The SPAD 502 Plus Chlorophyll Meter instantly measures chlorophyll content or “greenness” of your plants to reduce the risk of yield-limiting deficiencies or costly overfertilizing. The SPAD 502 Plus quantifies subtle changes or trends in plant health long before they’re visible to the human eye. Non-invasive measurement; simply clamp the meter over leafy tissue, and receive an indexed chlorophyll content reading (-9.9 to 199.9) in less than 2 seconds. Assess nitrogen needs by comparing in-field SPAD readings to university guidelines or to adequately fertilized reference strips. Research shows a strong correlation between SPAD measurements and leaf N content.
Instantly measures chlorophyll content or “greenness” of your plants on a scale of -9.9 to 199.9
Non-invasive, non-destructive measurement
Trend graph stores and displays up to 30 measurements
Compare in-field SPAD readings to university guidelines
Research shows a strong correlation between SPAD measurements and leaf N content
Available with or without a built-in data logger
Includes hard carrying case and batteries
Data-logging model (2900PDL)
Connects to any GPS receiver that has a serial output option*
Equipped with internal data logger and RS-232 port
Records 4,096 measurements (1,488 with added GPS/DGPS option)
Configure and download meter with FieldScout® software and USB-to-3.5mm-Stereo-Plug Adapther (Item 3661U.(included)**
Compatible with SpecMaps™ online web-mapping application
* GPS interface requires two cables. The GPS/DGPS cable (item 2950CV5) is available from Spectrum. A PC serial interface cable supplied by the manufacturer of the GPS receiver is also required.
** PC cable connects to a computer USB port.
 Hu Hao, Bai Youlu, et al. Study on nitrogen nutrition diagnosis of winter wheat based on SPAD-502 and GreenSeeker [J]. Chinese Journal of Ecological Agriculture, 2010, 18(4):748-752.
 Zhang Guolong, Chen Jian, et al. Using GreenSeeker and SPAD to monitor the occurrence of cotton aphid [J]. Northwest Agricultural Journal, 2014,23(5):171-176.
Optical Density Difference at two wavelengths: 650 nm and 940 nm
Measurement Area: 2 mm x 3 mm (Approximately 3/32 in x 1/8 in)
Light Source: 2 LEDs
Receptor: Silicon Photodiode
Power Source: 2 AA alkaline batteries (1.5V)
Repeatability: Within ±0.3 SPAD unit
SPAD Value: Index of relative chlorophyll content; -9.9 to 199.9