Every seasoned indoor gardening expert knows the importance of having LED grow lights. They are not only pocket-friendly but are also energy efficient, meaning that you don’t have to worry about enormous electric bills.
LED grow lighting panels are also effective because they emit both red and blue spectrums, which guarantee your plants’ high yields. Best of all: is that LEDs last many years compared to rival grow lights like HIDs and HPS.
The only problem with LED grow lights (basically with all grow lights) is finding the right distance or height from the plants. If done poorly, you can end up burning your plants, and that’s a loss you aren’t ready to bear.
With the right LED grow light distance chart and guideline, you’ll be providing your plants with the right PPFD, which is the number of photons required by plants to guarantee high yields.
The PPFD (photosynthetic photon flux density) is the equivalent of calories human beings need for growth and better health. So, once you have the right distance to hang the LED lighting, you’re halfway to 99 percent high yields.
Although it may sound simple and easy to determine the right LED distance chart, it takes a little research and accustoming yourself to how the lighting emission within a grow tent works. That is, you need to know how the distance from plants is affected, and which factors affect its efficiency.
Let’s have a look at how different aspects factor into LED grow light distance charts.
Wattage
This is the power emitted by the LED panel you’re using. The wattage can either help you out with the plant’s yields, or it can burn all of them out. So, as expected, it’s best to be very careful and always use an affordable wattage meter to determine what’s best for the plants.
However, the wattmeter would be ineffective if you don’t know the exact wattage to use. Depending on the LEDs you’re using, the distance from the plant’s canopies varies from 12 to 30 inches. Also, depending on the plant’s growth stage, you can adjust the LED’s height.
Here’s a grow light chart based on the LED’s wattage.
| WATTAGE | DISTANCE in INCHES (From Plant’s Canopies) |
| 200 to 400 | 12 to 20” |
| 400 to 600 | 20 to 28” |
| 600 to 800 | 30 to 38” |
| 800 to 1000 | 33 to 42” |
| 1000+ | 36 to 47” |
Growth Stage
For Seedlings – when the plants are in their germination stages, little to no light is required. Some even germinate faster in darkness – but that’s another story another day.
The need for little to no light is based on the fact that seedlings require very little energy to sprout their seeds. Therefore, it’s recommended to hang the LED lights as far away from the seedlings as possible. Also, make sure the LED lighting doesn’t emit high wattages – 100 watts is enough.
Novice indoor gardeners tend to make the mistake of intensifying the lighting immediately when they see some seedlings sprouting. Please DON’T. The intention, apparently, is to promote faster growth. Well, this is a mistake, and you can burn out some of your seedlings, or stunt their growth instead.
Just follow the LED grow light distance chart and you’ll be okay. Maintain a 100 wattage and a 20-inch distance. Once the roots have started coming out, you can very gradually minimize the distance but maintain the low wattage. Do this until the Veg stage.
For Veg Stage
Now, this is when the plants start maturing up, and so they’ll need photosynthesis to grow faster.
Once again, be careful with your LED’s wattage. However, you can comfortably intensity the LED lighting. If the panel comes with a setting to change the spectrum to include red and blue lights, then it’s best to do so. The UV comes in handy when promoting the faster growth of indoor plants.
Use the following grow light LED distance chart to confirm the required wattage and spectrum.
| WATTAGE | VEG Distance (inches) | FLOWERING Distance (inches) | SPECTRUM (nm) |
| 200W | 12 to 20 inches | 8 to 12 inches | 380 to 780nm |
| 220 to 400w | 16 to 30 | 16 to 18 | 380 to 780 |
| 450 to 650w | 24 to 30 | 16 to 20 | 380 to 780 |
| 600 to 800w | 32 to 36 | 18 to 22 | 380 to 780 |
| 850 to 1000w | 36 to 42 | 18 to 24 | 380 to 780 |
| 1200w | 30 to 37 | 18 to 25 | 380 to 780 |
| 1500w | 32 to 38 | 24 to 30 | 380 to 780 |
| 2000w | 26 to 30 | 18 to 24 | 380 to 780 |
For the Flowering Stage
This is when the plants go through the bud production and stem acceleration.
It’s important to raise the height further away from the plants but do it gradually. You don’t want to cut off lighting and surprising the plants such that they are unable to handle lighting intake. Still, don’t leave the LED lighting too close to the plants.
Note the LED lighting chart above if you aren’t sure of which distance from the plant’s canopies to use.
Also, it’s worth noting that plants in this stage usually have achieved their maximum heights. Therefore, lighting that’s too close to the canopies may end up burning the leaves and flowers.
Grow Light Timing & Type of Plant
This is basically like asking the question: How long should I leave the LED grow lights on for maximum yield?
Well, that depends on the type of plant. Some plants need longer daylight to flower. Similarly, some plants flower faster when exposed to more darkness than light. The latter type of plants (need longer darkness) is known as the “Short-Day” plants, and examples include mustard greens, avocado, marigold, strawberry, and zinnia.
The Long-Day plants require more exposure to lighting, and examples include parsley, mint, tomatoes, basil, and cilantro.
Therefore, other than the growth stage and the wattage, it’s imperative you know what type of plant is – either Long-Day or Short-Day.
[su_note]For more detail read: How Long To Keep Grow Lights on Plants?[/su_note]
Adjusting LED Grow Light Wattage for Best Distance
While the lighting chart is perfect, you can always do your own experiments by adjusting the heights and changing the wattage to find out which works best with your plant. This is important because different people come from different regions, where weather and climate are different.
Thereby, if you’ve tried the LED grow light distance chart, and your yields aren’t to the maximum, I’d advise adjusting the heights on your own time. It might be expensive to test and try, but you’ll come up with the best distance for your plants – depending on your region.
To experiment, you can use different wattages and distances for 2 to 3 days, then move on to the next setting to see how plants react. Look for discoloration in leaves, rate of growth, the taste of plants after harvest etc.
Make sure to record your results – room temperature, outside weather, distances used, and even PPFD.
Once you’ve found the settings that bring about the highest yields, stick to it. The best way to find the right height or distance from the plant is using a PAR meter. This measures the required PPFD for the plants, and you don’t have to worry about checking the wattage from the LED grow light chart.
FAQs on LED Grow Light Distance Chart
Here are commonly asked questions on LED grow lights, and how you can best maximize your plants’ yields.
How Does PPFD Affect the Distance of LED Grow Light from Plants?
Apart from the wattage and stage of your plant’s growth, the PPF is a crucial aspect to take into consideration. What’s PPFD in grow lighting? This is the photosynthetic photon flux density, which translates to mean the number of photons landing on the plants from the LED source.
The photons play a major role in your plants’ photosynthesis, which is how plants get food and grow to maturity. The PPFD is determined by the brand of LED grow lighting you’re using and the ambient environment you’re located in.
The PPFD is measured using the PAR meter, which is a great all light consists of small packets of energy called photons. The number of photons emitted by a light source in the PAR range is known as the photosynthetic photon flux.
The amount of PAR photons reaching your plant canopy is measured in micromoles per square meter per second. This measurement is known as photosynthetic photon flux density or PPFD and the units are µmols/m²/sec.
PPFD is an important metric because it helps growers accurately measure the light intensity for photosynthesis at the canopy level.
What’s the Best Distance of LED Grow Light during Seedling?
Seedlings are delicate and should be started at the maximum recommended distance away from the LED grow light. A safe distance for all of the G8LED grow lights is 12-36 inches above seedlings to start, depending on the size of the light. Once the seedlings have sprouted and grown a root system for 2-3 weeks, the lights can be placed closer to the plants.
What’s the Best LED Lighting Distance For Cannabis
Cannabis plants need enough light for faster vegetative growth, photosynthesis process, and development of healthy buds. Some of the reasons cannabis growers prefer LED grow lights to other traditional grow lights is because they are easier to monitor and do not produce too much heat.
Even though cannabis requires lots of light for healthy growth and high yields, too much distresses the plants.
Therefore, you’ll want to hang your light no more than 12″ away from your plants. – Remember: after 12″ fluorescent lighting loses its power, so make sure you don’t raise it any more than 12″ above your canopy otherwise your plants aren’t getting light energy
During Vegetative Stage, What’s the Appropriate Grow Light Distance Chart?
At a fixed height, the plants will grow to an equilibrium distance, then grow wider and denser. If the lights are too close to the plants, the light intensity will be too high and the plants may exhibit stunted growth and discoloring. Follow the recommended distances and adjust as necessary.
Final Thoughts
Lots more growers are starting to use LED grow lights, but there’s a lot of confusion about exactly how to use them. One of the most common questions about using LED grow lights is how far they should be from plants.
Getting the placement of your grow light right is critical to making sure it is delivering the right amount of light in your plant.
The trick is understanding some of the underlying principles around how light is emitted, spread and accumulated, this whole grow light thing becomes a lot easier to wrap your head around.