What is PPFD and PBFD and How Are They Measured?

Photosynthetic Photon Flux Density (PPFD) is the metric used to measure PAR over a square meter. It is a total count of light energy (in photons) from 400nm to 700nm that reaches a particular point on a plane.  Photobiological Photon Flux Density (PBFD) is the metric used to measure PBAR over a square meter. It…

Light Meters and What They Are Used For

Light meters are devices used to measure the intensity from a light source given the distance in which the meter is held from that source. They capture the photons emitted from the light at a particular point on a plane. For example, if you were to hold a light meter 4 feet from your light, you…

What is a Photon?

A photon is a particle of electromagnetic radiation. Simply put, it is a single unit of light.  Photons are used to convert light into useful energy, hence Photosynthesis. They are measured in micromoles describing the amount of light coming from a light source. Plants can sense photons using their photoreceptors; the organisms or proteins of…

What is PPF?

PPF Photosynthetic Photon Flux (PPF) is the metric used to measure PAR. It is a total count of light energy (in photons) from 400nm to 700nm.  PPF is measured in micromols (μmol). Micromols are 10-6 of a mol (A mol is a unit of measurement). The measurement is classified in time, revealing how many seconds…

What is PBAR and PBF?

PBAR Photobiologically Active Radiation (PBAR) is a range of light energy beyond and including PAR. Defining the specific range for PBAR is difficult as there are discrepancies of which nanometers the range should include. Some use 300-800nm while others use 350-800nm or 280-800nm. It is important to pay attention to the range used for data…

Understanding Light Intensity

Light intensity is the amount of light measured over a certain area. In essence, it is how much light is being provided.  There are many ways to measure intensity. The type of measurement used depends heavily on the application. Light intensity is traditionally measured in lumens. Lumens represent how intense or bright a light source…

Sections of a Spectrum and What They Do for Plants

The spectral range includes ultraviolet, violet, blue, green, yellow, orange, red and far-red light energy. Below are the specific nanometer ranges for each section and their benefits to plant growth. UV = 280-400nm Gives the plant a solid base and creates protection for the plant. Enhances the color, taste, and aroma of the plant. Blue…

Why PAR Doesn’t Matter

Below are the spectral distribution charts of two EYE HORTILUX grow lamps with very different spectrums – the Daylight BLUE Metal Halide and the Standard Metal Halide. When the charts are compared side-by-side, the difference in the quality of the two spectrums becomes readily apparent. The BLUE delivers a broad, full spectrum for your plants…

What is PAR?

Photosynthetic Active Radiation (PAR) was derived from the McCree Curve. It is a total count of light energy (in photons) between 400nm to 700nm. PAR is the defined range of light energy that most effectively stimulates photosynthesis in plants. The PAR measurement (PPF) has quickly become a popular metric of the growing power of a…

The McCree Curve

The McCree Curve represents the average photosynthetic response of plants to light energy (see chart below). It was developed by Dr. Keith McCree in the 1970s based on his research of 22 plant species. He found that much of a plant’s development and response to light happened within this portion of the spectrum.  The McCree…