How far away should LED lights be from seedlings? 2021 Updated

If you’re trying to figure out the perfect distance between your plants and the LED lights nourishing them, you’re already ahead of the game. Too many growers overlook light placement or decide to wing it. At worst, the result is a struggling, unhealthy crop. At best, they don’t get the full benefits of choosing quantum board led grow lights to begin with.

You get bigger yields and more potent buds by using powerful full spectrum LED grow lights and keeping them just the right distance away from your plants

By positioning grow lights the right distance from your plants, you’ll create the highest levels of light your cannabis plants can use. Put your buds in this “sweet spot” light level zone, and they’ll reward you!

• 150W – covers 2′ x 2′ (0.6m x 0.6m) area


• 250W – covers 2′ x 2′ (0.6m x 0.6m) area up to 2.5′ x 2.5′ (0.8m x 0.8m)


• 400W – covers 3′ x 3′ (0.9m x 0.9m) area up to 3.5′ x 3.5′ (1m x 1m)


• 600W – covers 3.5′ x 3.5′ (1m x 1m) area up to 4′ x 4′ (1.2m x 1.2m)


• 1000W – covers 4′ x 4′ (1.2m x 1.2m) area up to 5′ x 5′ (1.5m x 1.5m)

With all grow lights, always do the “hand test” after you’ve positioned your light. If you put your hand where your plants are for 30 seconds, does it feel too hot for you? If so it may be too hot for the plants and the light should be moved a bit further away even if it’s already within the acceptable range.

Light is the number one underestimated factor of growing, even at the seedling stage. If seedlings don’t have enough light, they grow more slowly and can become leggy. Overall, growers who do not give seedlings enough light have longer crop timelines and higher rates of seedling mortality.

Why do growers mistake the level of seedling light?

• They don’t have enough lighting.


• They place lighting too far from seedlings (bad coverage).


• They don’t leave lights on long enough.  

You’ve got to keep two goals in mind: the amount of light you’re giving seedlings, and the coverage of light that you’re giving seedlings.

1) Amount of light:

We can measure the useful light to a plant (PAR—photosynthetically active radiation, or the parts of light that the plant can use to photosynthesize) in micromoles per meter squared per second (micromoles/sec/m²). The goal here is to deliver 120–150 micromoles/sec/m² of PAR to your seedlings.

Some people will use a PAR meter to figure out how much PAR they’re getting to their seedlings and will adjust the distance of their lights based on that measurement. Don’t worry—you don’t need one of those if you’re using LED bars or fluorescent bars. Just remember the following distances.

LED bars (like Phillips): 8–12 inches away from seedlings

T5 fluorescents: 5–6 inches away from seedlings

2) Coverage of light

The next question is coverage. You can usually just eyeball this to figure out how far apart your lights need to be to deliver the same intensity of light across your entire seedling tray.

Again, we’ve outlined two simple rules to follow if you’re using the most common seedling lighting types:

LED bars: 8–10 inches apart from each other

T5 fluorescents: 4–5 inches apart from each other

Stick to these rules, and your seedlings will be ready to transplant in no time.

ECO Farm ECOL 90W LED Grow Light Bar

Pros:

• Great spectrum and easy to switch lights between veg/bloom


• Produces high-quality plants for an LED grow light


• Looks very modern and sleek


• High quality


• Perfect for a single tent needing only one light

Cons:

• A bit pricey

ECO Farm LED grow light can be your great choice.

Illumitex Eclipse Commercial 150w Dual Bar LED Grow Lights

Pros:

• Powerful Full-Spectrum light quality


• 3-year full warranty


• Energy Efficient


• Easy to Operate

Cons:

• Flower Spectrum Could Be Better For Higher Yields


• Higher Price Tag

Because best led grow light give off so little heat, you don’t run much risk of causing heat damage by placing your fixture too close to the canopy. What you do risk is light burn. Unfortunately, the light burn is easily mistaken for nitrogen deficiency, and many growers wind up misdiagnosing their grow and addressing the wrong problem.

If your plants have light damage, you’ll see symptoms such as:

• Leaves point upwards.


• Bleaching, which takes the form of white or yellow discoloration, typically on the leaves closest to the light.


• Veins remain green even as the rest of the leaves turn yellow.

A nitrogen deficiency has similar characteristics, but there are a few notable differences.

• A plant with a nitrogen deficiency also develops yellow patches, but the damage starts from the bottom of the plant and works its way up, while light burn begins at the top, closest to the lights.


• In the case of a nitrogen deficiency, leaves wilt. In the case of a light burn, leaves turn upward and sometimes even become brittle.


• The leaves of a nitrogen deficient plant fall off on their own. This does not happen to plants suffering from a light burn.

If it sounds like your plant has a light burn, it’s time to reevaluate the placement of your LED lights.

The intensity or distance between your plants and LED lights is crucial to the health of your grow. Run the lights too high power or place the lights too close, and you can damage the plant. Underpower or hang them too high, and you miss out on the highest possible yields and potency.

Your best bet for getting the exact perfect height is to consult with the manufacturer of your specific LED light. If you’re still on the hunt for an LED light, include customer service as a consideration when weighing your options. Choose an LED grow light for seedlings manufacturer that offers easy access to expert insight. May be eco farm grow light can be your good choice, this brand is best with my experience!