Grow Light Distance Chart: How Far should Lights be from Plants

indoor plant and grow light

Whether you’re new to growing or you’ve been at it for a while, people are often surprised at how many different options they have when making an LED grow light distance chart . LED grow light distance charts can be determined by lumens, wattage, and even the age and maturity of your plants . LED lights produce less heat than conventional lighting which also changes how far they need to be from plants . If it sounds like this issue is too complicated, don’t worry, we have you covered . Here’s your guide to everything you need to know about setting up a grow light distance chart .

Your Best  LED Grow Light Distance Chart

The best LED grow light distance chart is all about spectrum and lumens. Spectrum is the measurement of the different wavelengths of light that a particular LED light pink can produce. Lumens describes the total output of that light. Lumens are essentially the power an LED light has and spectrum is the variety of light it can produce. Here’s a full spectrum LED grow light distance chart that you can use based on the power of your LED light and the spectrum needed by your plants.

Spectrum Lumens Vegetative Flowering
380-780 nm 9600 12 to 20 inches 8 to  12 inches
380-780 nm 12250 16 to 30 inches 16 to  18 inches
380-780 nm 15200 24 to 30 inches 16 to 20 inches
380-780 nm 15630 32 to 36 inches 18 to 22 inches
380-780 nm 22216 36 to 42 inches 18 to 24 inches
380-780 nm 38966 30 to 36 inches 18 to 24 inches


One thing that you already have noticed about this chart is that the spectrum is the same regardless of lumens. These two measurements can be independent of each other, but the spectrum must stay the same for these lights.

As it turns out, plants can only use a certain spectrum of light. The light outside of the spectrum just simply can’t be photosynthesized. This means that if your LED bank is generating light outside of the spectrum listed above, it can’t be used by plants.


Knowing the right distance for your LED lights is the best way to stay on top of everything you need to know about LED lights and growing plants. While we’re on the subject, it’s important to understand how plants absorb sunlight when determining the right distance between an LED light bank and the canopy.


The next aspect of our  LED grows light distance chart is how you can measure the light that reaches your plants. This is broken down into PAR, PPFD, and DLI.

These three measurements are key to growing any plant with LED lighting.

PAR— Photosynthetically Active Radiation

PAR is best thought of as the wavelength of light that your plants can utilize. Certain wavelengths will not be usable by some types of plants and PAR is how we measure what your plants can see.

Think about it this way. There are certain types of plants that humans can eat and certain types of plants that we can’t.              Lettuce is within the range of plants that humans can typically enjoy, but tree bark usually falls outside of that range. It’s the same for plants and light.

Cannabis uses light in the 400nm-700nm range.

PPFD—Photosynthetic Photon Flux Density

You don’t have to break out your Flux Capacitor just yet, even though we’re getting a little scientific, this concept is pretty easy to understand.

PPFD measures the amount of light that a particular light source can deliver to your plants. PPFD is a measurement of the micromoles of photons delivered to  1 square meter of your plant every second.

We like to visualize this the same way we think about watering our plants. A garden hose delivers a certain amount of water to every square meter of plants every second. The same concept is at work with LED lighting.

DLI— Daily Light Integral

The last thing that we need to know is the Daily Light Integral for your plants. This is the amount of light that your plants need daily to stay happy, healthy, and strong. You can think about this as the equivalent of the number of daily calories that a health plan should be receiving, but with sunlight instead of calories.

The Quick— Not So Scientific—Way to Check LED Light Levels

When it comes to making a grow light distance chart LED light users can trust, we use a lot of science.

We need to consider everything from the wavelengths of light emitted by those diodes to the wattage used by the light bank. However, what if we told you there was a quick way to check your light distance without having to break out the calculator?

It’s easy. Simply place your hand a few inches above the top of your canopy while your lights are on. If you can hold your hand there without it getting too hot, it’s at a good distance from your plants. Your hand should feel warm, but not uncomfortably hot.

Now, this will ensure that you don’t accidentally kill your crop with light that is too intense, but it won’t let you dial in a high-yield harvest.

How far should LED Lights be from Plants by Stage

One of the best ways to determine how far your grow light should be from your plants is by the stage of life that your plants are in .

Let ‘s take a look at seedlings, the vegetative stage, flowering, and clones to see how far LED lights should be from plants during each phase .


How far should grow lights be from seedlings? The grow light distance chart seedlings need might surprise you . Many growers operate under the misconception that they need to drench their seedlings in intense LED light .


Seedlings are incredibly delicate . This means that you’re better off placing your LED light 24 to 36 inches away from your seedlings . This will also ensure that you do not accidentally dry out the soil .

Vegetative Stage

Now let ’s look at the  LED grow light distance chart for plants in the vegetative stage .

This is the stage in your plants’ growth where they need the most sunlight . Your plants are now growing to maturity, and they need light to reach their flowering stage .

The grow light distance chart vegetables need is defined by the fact that your plants are currently bulking up . Bring those LED lights within  12 to 24 inches to ensure that your plants are getting all of the light that they need .

However, watch out for problems during this stage . Growers tend to get overzealous and bring the lights in too close which could hurt their plants .

Flowering Plants

Once your plants are at the flowering stage it is time to back off on the lights just a little bit . Your plants still need a lot of light to ensure that they grow high-quality flowers, but there are some pretty serious downsides to having LED lights too  close .

You should have your lights except between  16 and 36 in while your plants are flowering . This ensures that they get enough light to grow high-quality flower, but prevents them from accidentally developing a major problem we see with LED lights     that are too close during flowering .

If your LED lights are too close while your plants are flowering, the plant will grow more vegetative mass instead of flowers . It will start to sprawl out and grow bigger rather than putting that energy into flowering which is a huge loss for growers .

What About Clones?

The LED light distance chart looks a lot different from seedlings and mature plants . Clones require much more intense light to give them the best chance at not just survival, but thriving .

Clones are created by taking a clipping or a cutting from a mature plant and grafting that to an existing stem . This creates a genetic copy of the plant the clipping was taken from .

This is an ideal way to ensure potency, aroma, and make sure that your products are consistent across harvests . However,   clones are difficult to grow and require more nutrients than traditionally grown plants . This means that they require closer LED lights and seedlings .

Why Getting Plants too Close to LED Lights is Dangerous

Our  LED grow light distance chart  should give you a good idea of how close your plants should be to your light sources, but you also need to know the three big reasons why you should have optimal light distance from your crops .

The first reason why you need an Optimum LED light distance is the most obvious . If your lights are too far away, or too close, you could accidentally kill your crops . This is a rare occurrence, but improper light placement can jeopardize the health of your plants .

Then there’s quality assurance . You want to make sure that your plants aren’t pale and starting to yellow. While your crops still might be acceptable, you want to always ensure that you’re growing the best possible crops .

That ‘s because you’ll be competing with other growers who are putting your best foot forward when it comes to their                 products . This means that you’ll need every advantage that you can get to beat the competition including the right LED light distance from your plants .

LED Grow Lights Compared to Traditional Grow Lights

A grow light distance chart weed growers can rely on should look at how LED lights compare to traditional lighting . There are plenty of success stories of growers using LED lights when compared to traditional lighting .

In the world of providing adequate lighting to cannabis plants, you have more than a few options . LED lighting has become   the most popular option because it offers the best wavelengths of light, saves energy, and stays much cooler than traditional lighting .

Traditional lighting methods include fluoride, metal halide, high-pressure sodium, or ceramic lights . These had a much more narrow range of wavelengths and needed to be considerably further from your crops .


Thai is because all of these lights give off much more heat . They posed a greater risk to the health of your plants if they got too close and made things too hot .

LED Grow Light Distance by Wattage

Another way of looking at an LED light distance from plants chart is looking at the total wattage of the LED light bank. This is a great way of getting solid distances for LED lights when you’re missing other information .


Wattage Vegetative Growth Flowering
200 12 to 20 inches 18 to  16 inches
400 20 to 27 inches 13 to 21 inches
600 30 to 38 inches 18 to 30 inches
800 32 to 42 inches 19 to 34 inches
1000 36 to 46 inches 21 to 36 inches


You’ll definitely have noticed that there’s a lot of variance in this chart . The wattage is simply letting us know the total power of these lights, but it’s missing vital Information including wavelength, how the light is focused using mirrors and reflective    surfaces, and the size of the LEDs themselves .

LED lights tend to have much lower wattages than conventional lighting . You have options like the LED bar light which provides ample coverage at a fraction of the energy use of traditional lights .

You can use the specific LED grow light chart as a quick shorthand will you dial and more specific distances between your LED lights and your plants .

The Golden Rule of LED Grow Light Distance

Now let ‘s talk about the one golden rule that you should always keep in mind when using LED grow lights .

Each manufacturer of LED grow lights uses different diodes, reflective surfaces, spacing, and countless other factors it’s      going to change the potency and availability of the light that reaches your plants . This means that all of the LED grow light charts they’re going to have a little give-and-take when it comes to the total amount of light reaching your canopy.

The single most reliable way to get information about your LED grow lights is to contact the manufacturer. There’s a good   chance that your LED grow lights came with some information about distance from your plants, but it doesn’t hurt to reach out to the manufacturer to get detailed information .

Other Factors that Affect Your Lighting

There are a few other factors that affect the lighting setup that you’re going to need for your growing operation .

Whether you’re getting into the legal cannabis industry, growing some vegetables at home, or you have other plans in mind, the overall setup of your operation can affect the distance that you need to place your LED lights at .

Factors including soil moisture, temperature, and how close you’re positioning plants next to each other all come into play    when calculating the optimum lighting for your plants . You can even get expert help in building a custom LED grow lighting setup that is ideal for your situation .

Wrapping Up How Close Should Grow Lights Be To Plants

Now you know everything you need to build the right  LED grow light distance chart  for your plants .

The distance that LED grow lights should be from the canopy is determined by looking at the lumens and wattage of the LED lights as well as the growth stage of plants . You’ll need to move your LED lights throughout your plant ‘s life cycle in order to  ensure that they grow properly and have the nutrients they need to stay healthy.

When in doubt, you can always reach out to your LED grow light manufacturer and contact them about the right LED grow light distance for you .

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