Horticulture Lighting Terms

When searching for the best grow lighting solutions it is important to know that not all light specifications are relative in determining the effectiveness of a horticulture lamp or luminaire. Lumens, LUX, candela and wattage are metrics used to discern light efficiency and intensity in commercial and residential lighting applications so they are not an appropriate means of properly judging horticulture lighting. Instead, the terms PAR, PBAR, PPF, photon electrical efficiency, PPFD and DLI are all important metrics to understand when making a lighting choice for horticulture specific applications.

PAR

Refers to Photosynthetic Active Radiation and designates the spectral range from 400–700 nm. The photons in the PAR range effect other horticulture lighting metrics such as PPF, Photon Electrical Efficiency, PPFD and DLI.

PBAR

Refers to Plant Biologically Active Radiation and designates the spectral range from 280–800 nm. According to the American Society of Agricultural and Biological Engineering (ASABE), PBAR covers a more substantial range of light that effects plant biology. The PBAR measurement includes the PAR band from 400–700 nm as well as the ultraviolet radiation band of 280–400 nm and the far-red radiation band of 700–800 nm. Active Grow uses the latest spectrometer technology to see a lamp’s entire PBAR range.

PPF

Refers to Photosynthetic Photon Flux or a lamp’s total emitted number of photons or micromoles per second (µmol/s). PPF only measures the amount of photons in the PAR range and is currently the standard measure in determining the efficiency of horticulture lighting products.

Photon Electrical Efficiency

Refers to how efficiently a horticulture lamp can turn a unit of electricity into photons or micromoles in the PAR spectrum range. A unit of electricity in lighting is referred to as watts or joules. The efficiency of joules that create photons In the PAR range are referred to as joules per second (joules/s). In order to determine photon electrical efficiency you use the measurement µmols per joule (µmol/J). The Active Grow SG300 LED Grow Light features one of the most efficient photon outputs in the industry at 3 µmol/J at 18” above the plant canopy.

PPFD

Refers to Photosynthetic Photon Flux Density, which is the measurement of light photons that reach a target point. PPFD units themselves are the number of photons in the PAR range that land over one square meter per second or µmol/m2/s. Active Grow publishes detailed PPFD data over a 4’ x 4’ area at different heights for the SG300 LED Grow Light here.

DLI

Refers to Daily Light Integral or the amount of total photons in the PAR range that lands on a target point over the course of 24 hours. Different types of plants require different levels of micromoles per day or moles/day, so this metric is useful in determining the appropriate light levels required for specific horticulture applications.

Get Growing

By better understanding horticultural lighting terms you can make a more informed decision when choosing the right equipment for your grow. Please contact us at info@activegrowled.com with any questions.