If you want to max-out your yields, you need to make sure that your cannabis plants are receiving an adequate amount of light. With a lux meter, this all becomes easier than ever!
Some types of grow lights, such as MH/HPS bulbs, have a limited lifespan. In due time, they get increasingly dimmer, and this is why they need to be replaced at certain intervals. The light meter can reliably let you know when you need to replace your MH/HPS bulbs.
WHAT IS A LUX METER?
Both insufficient light and too much light can be bad for your cannabis plants. The light meter can help you ensure healthy plant growth throughout all stages. The proper amount of light, not too much and not too little, will reduce stress on your plants, preventing further issues like light burn and bleaching.
Prevents Some Plant Problems
A lux meter can help increase the yield of your cannabis plants—an obvious benefit to growers. With it, you can determine the optimal spots within your grow room, or you can use it to determine the proper distance from your lights to your plants. A light meter/lux meter also lets you know when the light you’re using is simply not enough for maxing out yields.
Ultimately, smartphone light meters only feature a camera-based sensor and software to process the information: There’s no photodiode, filter, or correction lens to accurately measure luminous flux like a traditional meter.
As we’ve alluded to, using a lux meter is one of the easier tasks you’ll face as a cannabis grower. After taking the cap off the sensor, position the meter at the height of your plant’s canopy. Record this reading and adjust the distance between your lights and plants accordingly.
Of course, to get a grasp on lux meters, one first needs to be acquainted with lux itself. In brief, lux (lumens per square metre) is a measurement of the intensity of visible light that hits a surface.
How to Increase Cannabis Yields With a Lux Meter
In terms of finding that sweet spot between your light source and the canopy of your plants, note that the ideal distance will differ according to the type of light, and the wattage of said light. Using common 400–600W HIDs as an example, we’d advise allowing 30–60cm between the canopy and the lamps.
So, if that’s the case, why wouldn’t you just pick up a PAR meter for yourself, and skip lux altogether? Well, it’s a simple issue of cost. While a basic light meter can be found for under $25, PAR meters can easily be in the hundreds.
So, you have your lux meter in hand with a reading, but no idea what the numbers indicate. How many lumens do your plants need? During vegetation (once plants have moved beyond the seedling stage and feature a few nodes), between 15,000–50,000 lux is ideal to support robust stem, branch, and foliage development.
Apart from the traditional lux meter, there are now smartphone apps allowing you to measure light levels as well! These use a sensor, like a traditional meter, but differ in other ways from the standard device. They can be useful, as they often display info in a handy graph or chart format, but many lighting professionals see these apps as inferior to the traditional device, as there is much more opportunity for issues to arise.