Grow Light Distance Seedling

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How far should LED grow lights be from plants?

So, how far should led grow lights be from plants if you are to get maximum yield and the healthiest growth?

It is a detail which is often overlooked but the thing is if you want to increase your yields and potency, you need to keep your grow lights at the right distance.

I know you are perhaps asking “but how far should I hang them? “

Well, no need to panic. I will be answering that question plus several others we have been receiving from our passionate readers.

But let me take you back first.

Why should you use grow lights?

For the best results, your indoor garden should mimic a natural growing environment as close as possible- complete with the ‘sun’.

The grow lights, therefore, acts as the sun from which your plants get the energy to grow.

The best part is that you have full control over the type of light to use and also how much light will reach your herbs.

Grow lights are suitable for seed starting for the simple reason that they help guarantee stocky, green seedlings.

A wintertime bumper harvest of salad greens and herbs can also grow nicely under lights.

How grow lights work

Grow lights are engineered to deliver wavelengths of light necessary for your plants’ growth.

Plants hungrily reach for this much-coveted lighting source exactly the same way they pull towards the sun when germinating outdoors.

Specifically, a grow light imitates the spectrum of natural sunlight.

Or, depending on the plant, it can incorporate a spectrum which has so far proved to immensely benefit a certain plant species.

Your plants may need varying types and volumes of light

Now, your plants usually need different types & amounts of lighting as they progress through different growth periods.

So, if possible, have a mix of several essential grow lights. This is the only way you can give your flowers the best possible lighting throughout the stages.

But there are other grow lights; so why LED?

Before I come to tackling the question of led lights for seed starting, I need to remind you the reason why LED lighting has exploded in the last few years.

Here is why LED beats incandescent lights, fluorescent lights, and high-intensity discharge lamps (HID)

  • Plants automatically thrive better
  • LED lasts longer
  • Your electricity bill remains low
  • LED grow light can be customized to emit specific wavelengths
  • LEDs are super-green (no mercury, lead or gas)

This is how to determine the correct distance

Even though LED grow lights pack all these advantages, they also happen to be the hardest when we come to estimating the ideal hanging height.

But at least, the following tips should help reduce your confusion

  • Looks can be deceiving

LED lights are deceptively strong, more so the blue and red mixed lights. While they look dim and don’t feel very hot, they can scorch your plants.

You must, therefore, keep a close eye on your garden, whenever you install a new light- that is until you have a good idea of the best hanging height.

  • Follow manufacturer’s recommendations

Most manufacturers provide a guide on the recommended hanging height. Rather than play the guessing game, start by hanging your lights at the stated distance.

Again, observe your plants.

If you notice any bleaching (leaves start to turn white), back your lights off.

However, if your plants look fine, move your light closer until you notice some bleaching.

Then push them back again. If you check well, your plants should be okay.

But don’t take your eyes off the ball- just in case they start starving or feeling more heat.

At this stage, exercise your judgment. You can easily note the point where your plants start growing robustly and turn lush green.

  • General guide

If you don’t have any recommendations about how close should a grow light be to plants on the package, the following general guidelines will help.

For LED lights growing little patches of herbs, spices and wheatgrass (15w-90w), go a minimum of 15″ away.

You will hang even further if you have higher wattage lights. Here is a summary;

WattageDistances from plants
240-400w16-30” away
450-550w20-30” away
600-850w24-26 away
900w+26-42” away
  • Rule of thumb

If getting your ideal grow light height above plants becomes a tough nut to crack, this is what you do:

Get your LED lights as close to your plants as possible without compromising their coverage area while leaving enough room for your plants’ growth

  • Change the distance as they grow

Also, always ensure that you either lower your lights then raise them as your herb grow taller.

Alternatively, you may raise the plants towards the grow lights early on before lowering them as they continue to grow

What if you hang the grow lights too far from your plants?

If you set your grow lights too far away, your plants move from normal to a stretched growth.

It occurs since your plants have to put in more effort and try to grow taller so as to be near your light source.

The problem with this is that all the energy that could have gone into producing fruit is now being used to stretch.

So, you will experience a reduced harvest by as much as 30%!

What if you set the lighting so close to your plants?

Setting your horticultural grow lights too near will also be detrimental. You can easily burn your plants, especially the tops.

If not, some growers have reported experiencing strange/ stunted growth.

Wrapping it up

The question of how far should led grow lights be from plants will depend on several things including the wattage, the plants you are growing and even the season.

Setting them too far harms your harvest while pushing them too close will burn your plants or inhibit the growth.

Therefore, work hard and get your LED grow lights for seedlings set up correctly for a fruitful garden

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