What is PPFD? Why is it important?

PPFD stands for “photosynthetic photon flux density”. PPFD is also a method of measuring light intensity. It represents photons in the range of par hit by photons per second in a given square meter (expressed in micro poles): μ Mol m (- 2) s (- 1) is the most basic and smallest light unit. Basically, what PPFD does is measure the intensity of light. This means that PPFD is one of the most critical indicators to evaluate the quality of LED grow lamps.

But PPFD is the most important for your plant. The most important is the PPFD value of orange / red wavelengths, because these wavelengths have the greatest impact on plant yield at flowering.

PPFD measures the amount of par actually arriving at the plant. This describes the number of active photons hitting the surface of a square meter area in one second.

A 2010 study on PPFD in marijuana found that between 1500 and 2000, it was the best place to grow marijuana indoors. However, this optimum range is not common in commercial grow lights because it consumes a lot of electricity and costs a lot in the long run. So you may use enough low grow lights to produce high yields.

The following shows at least how much PPFD is required for cannabis plants to grow and obtain at least part of their yield:

Seedlings, clones and mother plants can be successfully cultivated using 200 to 400 µ mol m-2 S-1 PPFD.

In vegetative growth, 400 to 600 µ mol m-2 S-1 PPFD is sufficient.

Flowering plants will enjoy strong light of 600 to 900 µ mol m-2 s-1.

For example; If you want to know the true light intensity of the lamp in the specified growth area (i.e. 4 ‘x 4’), you must average several PPFD measurements at the specified height. If your plant approaches the optimal PPFD value, your plant will grow and yield at a better rate during flowering:

700–1500 μ Mol m (- 2) s (- 1) is the range of plant growth during flowering, but it is also the average PPFD value.

In addition to PPFD, these are also important;

Whether to supplement CO2;

Plant growth stage: in the flowering stage, plants need more strong light;

Your specific strain: the dominant strain of Alfalfa thrives in stronger light than the dominant strain of indica rice;

Illumination period: the longer the illumination period, the lower the optimal PPFD value, and vice versa.

In a word. If you want an amazing yield, PPFD must not be less than 510 at flowering μ mol m（-2）s（-1）。