The driving factor in determining the best LED grow light depends on the area you need to cover. Customer’s always ask what light they need or which one we recommend, but without more information it is difficult to direct them. Therefore, knowing their ‘coverage area’ helps guide the rest of the LED grow light decision process.
You can find the Recommended and maximum coverage area of every light in its product discription!
It might be safe to assume that most home growers setup a grow in a 100 x 100 cm or 120 x 120 cm (3,3'x3,3' or 4’x4’) area. But some people grow in a 60 x 60 cm (2’x’2), 90 x 90 cm (3’x3’), 150 x 150 cm (5’x5’), or a rectangular area. Some home and commercial grows are quite large and require several fixtures. Knowing the exact space you want to grow in helps narrow down how small or large of a light fixture you need. Too much light is wasted money, but not enough light can lead to less than desirable growth and yields.
One of the specifications on an LED grow light is the ‘recommended coverage area’. We highly suggest that this is the first thing you consider when choosing a fixture. The ‘recommended coverage area’ specification should primarily be used for smaller grows that only need one or a few fixtures. But larger commercial grows that require several fixtures could require fewer fixtures due to the effect of light contribution from nearby fixtures. Commercial applications should always consult and obtain professional advice and often a light plan before installing lighting. A light plan shows how many fixtures are needed to obtain the light level targets in a given coverage area.
Figure 1: Examples of recommended PPFD (μmol/m2/s)
PPFD measures the amount of PAR that actually arrives at the plant, or as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. PPFD is a ‘spot’ measurement of a specific location on your plant canopy, and it is measured in micromoles per square meter per second (μmol/m2/s). If you want to find out the true light intensity of a lamp over a designated growing area (e.g. 4’ x 4’), it is important that the average of several PPFD measurements at a defined height are taken.
You can find the PPF / PPFD measurements of every light in its product discription!
Figure 2: PPFD measurements performed over a 120 x 120 cm (4’ x 4’) grid for an Optilux 640 measured at a height of 60,1 cm (24”).
Figure 3: Overlapping (“cross-hatching”) the light distribution from four Optilux lights projected in a 120 x 487,7 cm (4’ x 16’) area.
Figure 4: PPFD measurements performed over a 120 x 120 cm (4’ x 4’) grid for 4 x Excite fSpectrum measured at a height of 40 cm (16”).
Source: URSA | Fluence Bioengineering