Using a lux meter is an essential tool for any cannabis grower. It helps to optimise plant growth, prevent issues, and improve yield.
No, cannabis plants don’t just love light—they worship it. If you want to rear an impressive crop of high-quality weed plants, you’ll need to give them a ton of light. Whether indoors or out, giving your plants the right amount of light involves careful balancing different factors, including positioning your plants relative to your light source.
A lux meter, also known as a light meter, is just one way growers can check the intensity of the light their plants are getting. Even though it only tells half the story, it’s still a helpful tool when planning an indoor grow.
What Is a Lux Meter?
To understand lux meters, you must first be familiar with the term. In a nutshell, lux (lumens per square meter) is a measurement of how much visible light strikes a surface.
A lux meter is utilized to measure how strong the light is around your plants in cannabis growth in regards to their distance from the light source. With this, you can tell if an adequate amount of visible light is being received by all parts of the plant(s), or if some areas are missing out/absorbing too much.
What Is the Difference Between PAR & Lux Meters?
Although lux meters can give you an indication of light intensity, they leave out crucial information. This is where PAR meters come in. See, luminosity (lumens) is the measure of how much light is seen by the human eye, but cannabis plants also absorb light outside of this spectrum. Not only that, but because lux measures the quantity of yellow light favored, it gives preference to yellow light that cannabis plants don’t use for photosynthesis.
PAR meters measure the amount of light cannabis plants can actually use for photosynthesis, includinginfrared and ultraviolet wavelengths. PAR is important because it helps growers optimize their farms by managing canopy height, leaf positioning, and more to ensure maximum efficiency in terms of both yield and quality.
So, if that’s the case, why shouldn’t you just buy a PAR meter for yourself and eliminate lux? It’s all about money. While a low-cost light meter may be purchased for less than $25, PAR meters might cost hundreds of dollars.
Fortunately, however, luxury meters aren’t completely useless; rather, they don’t account for the entire amount of light your grow room/cannabis receives.
How Does a Lux Meter Work?
Lux meters measure light intensity in the 380–700nm wavelength range. They convert light into an electrical current using a semiconductor called a photodiode. Growers may now determine whether their plants are getting enough light (more on that below). The good news is that using a lux meter is extremely simple. It will not take long to get acclimated if you know what to look for.
Why Is Correct Lighting Important When Growing Cannabis?
Knowing that cannabis plants require light to photosynthesis, it’s easy to see how important it is to provide the sort of light that supports this process and the fundamental phase of flower development.
Cannabis does not require the same amount of light during growth as it does during bloom. While outdoor growers may vary their spectrum according to the seasons, indoor ones must be more hands-on.
Cannabis plants in their vegetative stage, which is when they grow leaves and bulk up, do best with blue light from 400 to 500 nanometers (nm). When the plant enters its flowering stage—when it blooms—it does better with red light at 620–780 nm. Growers using high-intensity discharge lights can take care of both stages by changing from metal halide (MH) to high-pressure sodium (HPS) lights as needed. Alternatively, some full-spectrum LED lights come equipped with a switch that allows growers to change the spectrum manually between blue and red as required.
As shown, it’s critical to measure the intensity of light as well as the wavelengths that plants are absorbing.
What Are the Benefits of a Lux Meter?
Lux meters, in general, are useful. They’re cheap to buy and simple to use. You can maximize light exposure for optimal growth by using a lux meter (i.e., big yields from sound plants).
On the other hand, you may verify if your plants are receiving too much light using a lux meter. This can help you avoid problems such as bleaching, stretching, nutrients, and more.
Lux meters are also useful in detecting when a lamp’s power is failing or deteriorating over time—don’t underestimate the usefulness of this gadget. Finally, lux meters may be quite eye-opening by revealing which parts of your grow room get the most light relative to others. From here, you can make decisions about how to use your resources more efficiently.
Lux meter benefits:
- Helps you maximise light exposure for bigger yields
- Helps you minimise stress on plants
- Helps you indicate the power of certain types of grow lights
- Tells you where light is most/least intense in grow room
How Much Light Do Cannabis Plants Need?
So, you’ve got your lux meter in hand with a reading, but you’re not sure what the numbers indicate. How many lumens do your plants require? Between 15,000 and 50,000 lux is ideal for robust stem, branch, and foliage development during vegetation (once plants have passed the seedling stage and have several nodes).
As the days get shorter, plants need more lumens to flower—around 45,000 to 70,000 lux. You generally don’t want to exceed 60,000 lux during vegetative growth and 75,000 lux in flowering because plant growth can start slowing down at that point and other issues might occur. It’s important to keep in mind that young seedlings and clones require much weaker light than both vegetating and flowering plants. Under 7,000lux is advised for them.
Different strains come from all over, so it only makes sense that they would have different light needs. A light-sensitive strain may do well with lower lux values, while a light-hungry one will need more – but only within the recommended limits.
How to Determine the Right Amount of Light for Cannabis Plants
The distance between your light source and the plants’ canopy should be different depending on the type of light and its wattage. For example, using common 400-600W HIDs, you should allow 30-60cm between the lamps and the canopy.
To determine how much light your plants are receiving, you may use the lux meter to measure from top to bottom. Keep in mind that as plants get farther away from the source of light, it gets weaker, so maintaining a delicate balance between providing your plants with enough light while avoiding burning and other problems becomes increasingly important.
Unlike other types of lights, it can be difficult to determine the light output of an LED using a lux meter. Instead, you need to use a PAR meter. It’s important to figure out which light is best for your grow room before getting started, as each type has different advantages and disadvantages.
How to Use a Lux Meter
As we’ve previously noted, one of the simplest jobs as a cannabis grower is to use a lux meter. After removing the cap from the sensor, position it at your plant’s canopy height. Keep track of this reading and alter the distance between your lights and plants as necessary.
Furthermore, check other areas of your plants for lux to ensure that all bud sites are receiving enough light. Also, use a lux meter to measure the amount of light in different parts of your grow room; this will help you identify any hot or cold spots.
Lux Meter Apps
Mehmet Cemil is a lighting professional who often uses his smartphone to measure light levels. He sees many benefits to this method, as the info is displayed in a handy graph or chart format. However, he acknowledges that there are some drawbacks compared to using a traditional lux meter, such as the increased potential for issues arising.
A smartphone light meter is only as accurate as the camera-based sensor and software processing the information: There’s no photodiode, filter, or correction lens to measure luminous flux like a traditional meter.
How to Increase Cannabis Yields With a Lux Meter
With a lux meter, you can increase cannabis yields by exposing plants to the right amount of light. You may find out the best location in your grow room and the optimum distance between your plants and their light source for optimum development and aproductive flowering phase with this measuring equipment. There’s nothing worse than attempting to cultivate using high-quality lighting but ending up with lower yields or burned crops because
Is a Lux Meter for Growing Cannabis?
Given their price and availability, you might as well pick up a lux meter – it could save your cannabis grow. At the very least, it can tell you if lighting is inconsistent in your grow room, or if plants are being blasted with way too much light. Especially for those using HIDs, CFLs, and “white” LEDs, a lux meter can tell you how many lumens are reaching the canopy.