How Far should LED Grow Lights be from Plants?

So you're thinking about building your own indoor grow setup but aren't sure where to start. When it comes to growing indoors, there's a lot of factors you need to be aware of. For example, you might wonder how far LED grow lights should be from plants?

Indeed, light placement is one of the most important elements in growing plants indoors. A grower must ensure that their plants get enough energy to grow at a healthy rate without being overwhelmed. If the light is set up too close or too far, your plants will likely be damaged. 

This question is hard to answer because growers tend to use different types and sources of light to nourish their plants. However, it remains to be said that most modern indoor grow setups tend to use LED (light-emitting diode) lighting. 

In this article, we'll explain how far LED grow lights should be from plants in your indoor grow setup.

How Close to Keep LED Grow Lights?

You can grow your plants indoors by using LED grow lights. Plants need space and time to grow outdoors, and usually, there isn't enough of either. Indoor gardening is a good option in these situations. Nevertheless, your environment is much dimmer, so it makes sense to take your time and ensure your plant growth system includes an integrated LED grow light for plants.

LED grow lights are best used at a distance of 12 to 30 inches above the plant's crown if you want proper lighting for indoor growing. Remember that this system will need to be adjusted as your plants grow. You can't keep giving a plant the same amount of light as it grows, so its requirements change.

LED Grow Light Distance Chart

Light intensity increases when the light source is located closer to the canopy. As a rule of thumb, grow lights should be installed closer to the canopy of plants during vegetative growth and further away during flowering.

 The chart above illustrates the effects of a 600W LED grow light on the plant canopy at various distances. This chart displays light intensity (lux), PPFD (μmol/m-2/s-1 or micromoles per square meter per second), and the light coverage of the canopy. With an increase or decrease in plant canopy distance from the light source, the intensity, PPFD/PAR change accordingly. 

Also highlighted in the chart is how a plant's canopy coverage changes based on the distance from a 600 watt LED light.

Distance between LED Lights and Plants During Growth Stages

It should be noted that the ideal distance between plants and grow lights varies based on the plants you have, the amount of natural light in the room, and the lighting wattage. It's near impossible to pinpoint the distance on the spot. You will need to experiment a little, but you will be able to make it work after some testing.

There are three stages that we need to take into consideration when adjusting our LED lights in our indoor growing setup. Below, we'll be discussing the three main stages for light distancing.

LED Grow Light Distance from Plant for Seeding Stage

Whenever the soil is dry, a seedling will not reach its full potential, which is why your LED lights should be placed higher above the canopy at the beginning of the growing period. While exposing young seedlings to short bursts of bright light to stimulate rapid growth can sometimes be tempting, this is not recommended! Light intensity should not be raised until the plant has matured from its seedling stage, so growers must be careful to achieve the best results.

Generally, LED grow lights are mounted between 24-36 inches above the crown of the seedlings. However, the distance of the light is still dependent on the wattage of the source.

Keep LED grow lights at a distance of 36 inches or more from seedlings - this will keep heat and light levels lower and prevent seedlings from drying out. When the roots have established, and sprouting begins, the lights can usually be moved closer within two to three weeks.

LED Grow Light Distance from Plant for Vegetative Stage

As seeds mature, the light spectrum requirements for the vegetative stage remain similar to the requirements for seedlings. The light intensity needs to be increased to ensure that the plants produce a good yield and photosynthesize properly. 

Typically, LED grow lights should be 12-24 inches above the top of the canopy during vegetative growth. Photosynthesis requires more light during the vegetative stage, which is why plants should be placed closer to a light source.

LED Grow Light Distance from Plant for Flowering Stage

As plants reach the flowering stage in their life cycle, they need the highest light intensity levels possible to maintain continued stem growth and blooming - this is the final stage of growth, after all. LED lights have to be moved closer to the canopy to achieve this. 

To achieve the best results, you should gradually bring the LEDs closer to the plants. You will need to reduce your light distance slowly to achieve the optimal distance between the light source and your plants.

It is recommended that the top leaves of the canopy be between 18 and 24 inches away from the light source so that flowering can occur. This is when plants grow tall and bear fruit. During flowering, the height and distance of the lights don't need to be changed, especially if you do not want taller plants.

Can Grow Lights Burn Plants?

Plants often show symptoms of distress when exposed to too much light, regardless of their growth stage. LEDs produce very little heat, so monitoring the plants for any signs of being slightly burned is crucial. The plants may also become discolored or have their growth stunted when the grow lights are placed too close to the plant canopy. In both cases, the grow lights must be adjusted immediately.

In a burning plant, thin brown lines first appear along with the leaves closest to the light, and then larger areas start to become discolored. Remember that what may appear to be a light burn can actually result from nutrients burning inside the plant.

In addition, regardless of whether you regulate light proximity by testing out different distances, LED lights are advantageous due to their low infrared emission levels. Consequently, even if you don't get it right on your first try, LEDs are more flexible and won't burn you or the crop right away.

Mistakes to Avoid When Using LED Grow Lights

Some people do quite well growing at home, whereas others don't - their plants wither quickly or produce poor crops. Improper lighting usage can cause these problems. When used improperly, grow lights can be harmful to the plant and make the process of growing more efficient.

Here are five things you should consider when using LED grow lights to grow healthy plants and avoid unnecessary problems.

• Overheating- The plants that are closest to the light will begin turning brown if they are taking too much heat. As soon as you see thin outlines on the leaves, you will have a chance to stop further damage. Curled leaves could also indicate that the plant is too close to the light. Effective ventilation can help here as well.
• Insufficient Lighting- Calculate how many LED lights you will need for the plants that you're growing. Also, pay attention to the brightness of the lights you use. Don't overdo the lighting, but make sure that you have enough lamps.
• Poor Lighting Distance- The plants could overheat or be underlit if the lights are placed too close or too far from the plants. The recommended distance between the LEDs and the plants is 12 to 18 inches. However, there is no universal rule for determining the distance.
• Low-Quality Products- In order for plants to grow, it is vital to pay attention to the light, as it triggers photosynthesis. Plants will not grow very healthy if you use regular incandescent lights. Using full-spectrum LED grow lights is therefore recommended for best results. The bulbs are specifically designed for helping plants grow and emit light with the correct spectrum.
• Unadjusted Lights- Often, people don't adjust the height of the lights as their plants grow bigger, and the leaves end up burned. To avoid too much leaning towards the light by a specific part of the plant, it is essential to rotate the pots periodically.

Wrap Up!

Growing plants isn't a quick process, and everything needs to be calculated and accounted for. Knowing how far LED grow lights should be from your plants is crucial in producing healthy crops from your indoor plants.