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Industry Terms

Horticulture Industry Terms

We have compiled some of the common horticulture and LED lighting terms used when explaining our products.  Feel free to use this cheat sheet when navigating through our site and information.


Photosynthesis is the process in which plants take energy from light to convert water and co2 into nutrition or “plant food”.

PAR:  Photosynthetic Active Radiation

The PAR, or photosynthetic active radiation, is the amount of light that is usable to plants.  This light enables photosynthesis to occur.

PPF:  Photosynthetic Photon Flux

 Photosynthetic photon flux, or PPF, is what measures PAR in a light source.  PPF tells us the amount of all photons emitted from a light source in all directions per second.  The measurement is calculated in umol – or micromoles per second.  The higher the PAR, the more a plant is able to photosynthesize.

PPFD:  Photosynthetic Photon Flux Density

Photosynthetic photon flux density, or PPFD, is what measures how much of the PAR from a light source actually reaches a particular surface.  This is measured in the amount of Photons that hit one square meter per second.

PPE:  Photosynthetic Photon Efficacy

Photosynthetic Photon Efficacy, or PPE, is a measurement of PPF divided by Watts needed to power a lamp.  This measurement tells us how well a particular lamp can produce the light spectrum we need.

DLI:  Day Light Integral

 The DLI, or day light integral, is the amount of PAR a plant receives during a period of time.  We calculate the DLI of a plant using the following:

Electromagnetic Spectrum:

 The electromagnetic spectrum is a range of all wavelengths.  This spectrum is arranged according to frequency and length of wavelengths.

Visible Light:

 Visible light is a small portion of the electromagnetic spectrum which contains light wavelengths that humans are able to see.  Typically, humans can see wavelengths from 380-700 nanometers.


A nanometer is a unit of measurement that is equal to one billionth of a meter.


UV, or ultraviolet light, is a light spectrum which has wavelengths shorter than visible violet light but longer wavelengths of x-rays.  It provides particular benefits to plants such as resin & essential oil production, activation of natural defense mechanisms, and acceleration of the germination process.

Blue Light:

Blue light is a wavelength or color in the visible light spectrum which serves as a plant indicator of the general intensity of light, as well as a regulator of the opening of stomata in a plant.

White/Green Light:

White/Green lights are wavelengths or colors in the visible light spectrum which are longer than those in blue lights, but shorter than those in red lights.

Red Light:

Red light is a wavelength or color in the visible light spectrum whose wavelength is longer than that of blue, white, and green light.  Red light promotes growth and flowering in plants. Red light fits with the absorption peak of chlorophylls, which stimulates photosynthesis to produce sugars and carbons.

Far Red Light:

Far-red light is a wavelength or color which is at the extreme end of the visible light spectrum, coming just before infra-red light.  This light can imitate shade for plants, as well as promotes plant growth.  High amounts of far-red light can also decrease the amount of chlorophyll, anthocyanins, and antioxidants, and increase the flowering in many plants.

Color Combinations:

When a grower combines different colors in the light spectrum.  These combinations can develop specific characteristics in plants.