When it comes to LED lighting, a lumen is a common term you will be coming across, and it refers to the unit of measure used in place of watts. A lumen refers to the amount of light a particular light produces or its luminous intensity. A commonly confused term is ‘lux,’ which refers to how either how spread out or focused the LED light source is. A perfect example would be the comparison between a laser and a regular bulb, in which case the laser has a higher ‘lux’ value. The intensity or quality of the light can be estimated by its cumulative power draw. More lumen implies a higher power draw and vice versa.
The choosing process
The effectiveness of the LED grow light is estimated by the level of photosynthetic activity radiation (PAR). This is a grow light term used to describe the light spectrum type used by plants. This covers the spectral range of 400 to 700 nanometers of the spectral range that is also visible in the natural light. Unlike the human eye though, plants lean towards the light at both ends of the spectrum. This is the light photosynthetic beings use, so you need to search for a grow light that imitates this light spectrum. PAR is measured in micro scale units, shortly known as uMol. This refers to the photon flux density of light the LED grow light emits per meter squared for every second. PAR ratings should exceed 600 uMol for a LED grow light to be considered effective in aiding the growth of plants through photosynthesis. Platforms such as Lumi Growth can help you out if this seems too complex.
Avoid LED grow light companies offering a single PPFD estimate unless you intend to grow a single plant under your light. Keep in mind that by grouping the LEDs firmly together and with the use of narrow beam optics the manufacturer can easily demonstrate high PAR measurements. This is because most LED light systems pool the LEDs to a small fixture footprint which consequently exhibit high PPFD levels in the area directly beneath the fixture. Nonetheless, these PPFD levels are bound to drop the farther you are from the fixture
Caution should be taken when purchasing a LED grow light, so as not to be confused by wattage, different LED grow lights have different efficiencies, and as such, the wattage is not necessarily an important factor. Keep in mind that the LED wattage is an input and as a grower, you are more concerned with the output. The LED grow light’s wattage does not reflect its capacity to deliver light to your plants.
When it’s all been said and done, you want to acquire a LED grow light system that will efficiently deliver the right amount of lumen required by your plants at the lowest cost, while at the same time consuming the least electrical watts if you are to realize a good return on this investment. With this in mind, you need to be furnished with data such as PFD maps for the predetermined grow area, input watts and PPF by the manufacturer.