Apogee’s rugged new meters make it easier than ever to take research-grade spot measurements of PPFD, while also recording daily light integral (DLI) and photoperiod in one simple to use device.
Based on your application, the three different meter models feature different spectral responses and can take instantaneous readings of PAR or ePAR while automatically recording the daily light integral (total photons in mols) and hours of light (photoperiod in 0.1 hours) in any location for up to 99 days. This data can then be viewed on the screen by toggling the button or downloading via an included USB-C cable.
Three Models
DLI-400: Lowest-cost option is accurate for measuring 400-700 nm only in sunlight and under some broadband light sources.
DLI-500: Full-spectrum is accurate for measuring 400-700 nm under all light sources including LEDs.
DLI-600: ePAR is accurate for measuring the newly discovered extended PAR (ePAR) 400-750 nm range under all light sources.
DLI Meters Intro with Dr. Bruce Bugbee
Accurate, Stable Measurements
Meters are cosine-corrected to maintain accuracy when radiation comes from low angles (± 5 % at 75° zenith angle). Long-term non-stability determined from multiple sensors in accelerated aging test and field conditions is less than 2 % per year.
Data Collection and Display
Meter displays real-time PPFD/PAR or ePPFD/ePAR in µmol m-2 s-1; daily light integral (DLI) in mol·m-2·d-1; and photoperiod in 0.1 hour increments. DLI and photoperiod measurements are recorded continually every three minutes with a darkness threshold of .1 µmols and the meter can also display the instantaneous data for spot checking areas. Daily data is stored up to 99 days and displayed onscreen by toggling through the screens. DLI, photoperiod, and 30 minute PPFD averages can be downloaded as CSV files via the USB-C port under the battery cover using the included USB-A to USB-C cable.
Rugged Design
Housing is built tough to withstand harsh environments and is dustproof and water resistant up to IP65. Unit consists of a cast acrylic diffuser (filter), optical filter, photodiode, signal processing circuitry, LCD display, and two AAA batteries (included).
Warranty and Support
All Apogee products are backed by an industry-leading four year warranty and outstanding customer support.
Mounting
Unit can be placed directly on any flat, level surfaces or mounted by attaching to commonly available camera tripods, clamps or stakes using the standard camera-sized ¼-20 threaded port in the bottom of the unit. A small plastic soil stake is included for standing the unit in turf or other soft soils.
Typical Applications
Monitoring PAR or ePAR intensities, daily light integral, and the photoperiod of grow-lighting is critical for plant health, growth rate, photosynthesis levels, plant morphology, and crop steering. Required levels vary greatly by species and should be measured and controlled for optimum specimen health.
Calibration
To ensure accuracy, each DLI meter is carefully calibrated in controlled conditions and traceable to NIST reference standards.
Plants have a unique set of light conditions under which they perform best. Purdue's list of DLI requirements for common greenhouse crops (pages 5-7) may help you identify how many moles of light your crop should be getting each day.
