LED Grow Light Distance Chart
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LED Grow Light Distance Chart, how to position your grow light?

The right light is the foundation of successful indoor plant growth. It's not just about what kind of light to use, but where to put it. With so many different types and shapes of LED grow lights available on the market today, it can be overwhelming to figure out which one will work best for your specific needs. To help you make this decision, we have created an informative post on LED Grow Light Distance Chart, how to position your grow light?

How Far Should Your Grow Light Be From Plants?

The general rule is to keep your grow light around one foot above the top of the tallest plant in a vegetative state and slightly lower (18-24 inches) when it’s time for flowering. However, this isn’t always true because many factors, such as the type of LED panel used, wattage, and spectrum output, come into play. For example; full-spectrum red Veg/Bloom lights should be placed 12″ away from plants during propagation (vegetative growth), then moved up about eight inches every two weeks until you reach 24″ or whatever height your lamp emits optimal PAR readings at that distance. Then, of course, once they begin entering their flowering phase, you will want to move them back down again, so they are 18″ or 24″ above the tops of your plants.

indoor cannabis grow plantation with plants under

It is recommended to keep full-spectrum white LED grow lights 12 inches away from your plant canopy during their vegetative state, then move them up every two weeks until they are 18 inches or so above your topmost leaves when it is time for flowering. For HPS/HID lighting, you should place the light around one foot over the tallest plant in a vegetative state and slightly lower (18-24 inches)when it’s time for flowering. But, again, this isn’t always true because many factors, such as type of lamp used, wattage, and spectrum output, will determine how far apart to space each bulb on average, depending upon its actual power.

Why Is The Distance Between Grow Lights And Plants Important?

The distance you place your grow lights from your plants is vital because it will determine the intensity of light that reaches them. If they are too close, there may be hot spots on some leaves while others won’t receive enough direct sunlight, which will cause low yields and poor growth. On the other hand, if they are placed too far away, you might not get good penetration to all parts of the plant canopy, so again this can lead to lower yields than expected. Most LED panels emit optimal PAR readings between 18-24 inches above their topmost leaves when in a vegetative state. Still, different types/brands vary slightly due to differences in spectrum output frequencies (colors). Generally speaking, growers should follow these guidelines for proper lighting placement depending on the type of LED light they are using.

Average LED Power Output Per Unit: 400W – 1000W (watts) - PAR rating at 18” above the canopy with a 24” diameter footprint. Lamp Diameter Size Range: 48″ – 96″ wide and high wattage lamps typically come in 30-36 inches long sizes for this type of lighting technology, so you must ensure there is enough room between fixtures to allow adequate airflow as well as space needed for proper cooling. Bulbs should be spaced around 16-24 inches apart, depending on the unit's overall length and actual power output per lamp.

Why is LED lighting crucial when growing plants, including marijuana, indoors?

LED (light-emitting diode) lights are more efficient and easier on electricity costs than other types of grow lights available today. They also emit less heat which is essential because it means you can place them closer to your plants without burning or damaging them, especially during the hot summer months when temperatures need to be kept low for optimal growth and to prevent mold from forming. Growers should never forget that light quality matters just as much as quantity, so make sure you purchase a full-spectrum LED panel if possible with built-in UV and IR frequencies rather than using those separate items because they work better together to provide complete coverage versus only specific colors within the spectrum range such as blue and red alone like some cheaper models may have. This particular chart is based upon LED grow lights with a PAR rating of 400-1000 watts which emit optimal light intensity (brightness) between 18 and 24 inches above the topmost leaves in a vegetative state.


Grow lights are crucial in the vegetative growth stage of your marijuana plant because they need to receive 12 hours or more of continuous morning per day, which is measured from the start point (when the indoor grower turns on his HID/HPS lamp for the first time) until endpoint when it shuts off. This is critical during this stage because they will develop their main stem and branches, which ultimately determines how well your plant performs at the end of its life cycle. If, for example, you don’t provide enough light during this stage due to incorrect lamp positioning or low wattage for room size, then there may be a lack of secondary branching with smaller yields than expected, so always remember to check light distance throughout your plant's life cycle.

Recommended LED Grow Light Distance Above Plants

When using LED lights, people have been concerned about heat damage for some time now because of their reputation as being so bright and powerful, but this has been a myth that is not true with these types of grow lamps, especially when they are spread out properly around your plants at recommended distances so you can avoid wasting energy or overheating them which will cause burning/scorching issues on the leaf tips. Many growers report excellent results by placing them directly on individual pots within an enclosed hydroponic system without reflectors/hoods due to light intensity per square foot output from each panel used. Some even create homemade PVC pipe lampstands to be mounted directly onto PVC piping, where they can be hung above their plants like a showerhead. The key is knowing how far away from your plant you should place each LED grow light because placement distance varies depending upon the room's size and total wattage being used, so it’s best to measure that out first fixtures or setting up hanging cords.


In general, smaller sized units such as those with PAR ratings between 400 and 600 watts output optimal photosynthetic photon flux density (PPFD) levels within a 12-18 inch diameter footprint when measured 18 inches high on top of most indoor cannabis growing mediums at vegetative growth stage which would include coco coir, soil/soilless mixes as well as hydroponic solutions. In addition, growers using these smaller models can place them closer to their plants during the vegetation phase without fear of burning or damage because they do not produce much heat at all, and it’s recommended for optimal growth results before switching over to a complete flowering cycle.

LED lighting for marijuana plants

LED lighting is a highly recommended growth method these days, even with its higher costs, because it is very efficient and cost-effective in the long run due to lower power consumption, especially for those large commercial operations. Many growers have been able to reduce their electric bill by over 50% per month, which makes a big difference when trying to save money, so now more than ever, LED lighting has become mainstream for this industry and hobbyists alike who are growing at home.

Grow lights emit different flavors of light depending upon what they’re made from, but most often, you will find red or blue-tinged panels used during the vegetation stage. At the same time, white/warm colors such as yellow, orange, and pink are preferred during the flowering cycle, just like natural sunlight. The most popular models on the market emit light in both spectrums because they provide a natural look to your plants which is preferred for either type, but there are more benefits than just appearance with full-spectrum LED grow lights.

cannabis indoor farm

Which other plants may benefit from LED lighting?

It’s a known fact that LED lights are great for marijuana plants but did you know there are other indoor growing operations where they may also be beneficial? For example, many growers have found success using them for their houseplants by hanging them from the ceiling in front of large windows, but this is not recommended while your cannabis plants are still small so if trying out these new technologies on other species, first always keep track to see what works best. You can even add some supplemental lighting during the flowering stage to give them an extra boost when needed because it will affect all vegetation types, especially those requiring little light, such as African violets and spider plants which thrive indoors under low-light conditions or outdoors in areas with no direct sunlight.

When Should You Adjust Your Grow Light’s Distance From Plants?

Like growing marijuana plants, the distance your LED grow light is positioned away from your plants varies depending upon wattage used and room size, so this number should always be measured before installation. It doesn’t matter what type of setup you are using either whether it’s a smaller model or larger unit, because placement will vary based on several factors, including how much heat they produce as well as total output which can cause damage to foliage if placed too close for an extended period without proper ventilation. Even though these panels don’t output very high humidity levels during the vegetation phase compared to HID lighting setups, make sure you keep all other variables in mind, such as temperature fluctuations due to carbon dioxide (CO) emissions from the light being used.

What are Some of Its Benefits?

LED grow lights have become quite popular in recent years because they use less energy and produce far less heat when compared to other lighting options such as HPS or MH lamps which allows them to be placed much closer during the vegetation phase before switching over for the flowering stage. In addition, these types of panels emit tiny amounts of humidity, so you don’t need any cooling system installed if your room doesn’t already have one. Still, it never hurts to play it safe just in case unexpected issues arise that could cause damage which means placing ventilation systems at least ten feet away from plants, especially those using carbon dioxide (CO) rich bulbs emitting high humidity levels.

Which colors affect which stages of vegetation?

As mentioned before, red and blue-tinged LED panels are used during the vegetation stage of growth because they mimic the sun's natural sunlight, preferred for this phase. On the other hand, white or warm colors are more prevalent during the flowering cycle, just like natural sunlight, so you will find many models on the market being manufactured with both spectrums to provide a balanced look throughout each vegetative period. Still, there are even more benefits than just appearance provided when using full-spectrum lighting setups, such as increased photosynthesis rates due to higher amounts of light penetrating through foliage than HPS lamps emitting high levels of heat in comparison. As long as your plants receive at least ten hours per day without interruption along with proper control, they should flourish quite nicely.

cannabis grow plants

How to Notice If the Distance and the Intensity Are Wrong?

Growers should take note of the leaf structure to determine if there is too much light or not enough when using LED panels during the vegetative phase. If you notice that your plants are stretching out looking for more light, this means they need less distance from the panel, which can be adjusted accordingly. Still, if leaves start turning yellow, then it’s time to move them further away. Otherwise, their photosynthesis rates will decrease, leading to nutrient deficiencies and possible death, so always keep track no matter what type of lighting setup you use. Also, like with HPS lamps, these panels emit high heat levels, so ensure all foliage has proper ventilation nearby, especially those requiring lower amounts, such as African violets or spider plants growing indoors under low-medium light levels.

LED grow lights are becoming more and more popular because of their many uses, ranging from helping people start hydroponic setups to providing supplemental lighting for houseplants during low-light conditions or even on entire farms where energy efficiency is a significant factor.

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