Grow Lights

How Far Should Seedlings Be from a Grow Light?

When Should You Start Worrying About Your Plant Getting Too Hot

Many people have questions about how far seedlings should be from a grow light. The answer is not as simple as you might think. Seedlings need a lot of light to grow.

Too much light can be harmful, but not enough light will stunt the growth of your seedlings. The question is, how far seedlings should be from a grow light?

In this blog post, we’ll discuss the optimal distance for healthy plants and what happens if they’re too close or too far away.

What Is A Grow Light and What Do They Do?

A grow light is an artificial light that is used to supplement the sun. A grow light usually emits wavelengths from the blue and red ends of the spectrum.

LED vs. fluorescent grow lights? An LED grows light is one of the most efficient types of grow light on the market because it uses significantly less energy than other types.

The main job of a grow light is to make photosynthesis possible for plant life by emitting certain wavelengths into the air. Photosynthesis is critical for all plants, but especially for seedlings since they’re just starting.

When using a grow light, the goal is to put it close enough so that photosynthesis can occur in its optimal range, but not so close that it becomes harmful to your plants.

How Far Should Seedlings Be from A Grow Light?

Seedlings should not be too close to a grow light, and they should not be too far away from it. The optimal distance for photosynthesis to occur is about 18 inches to 27 inches.

If the LED grows to light closer than 27 inches, it can start to affect your plants negatively. Photosynthesis cannot occur in this range because the emissions cannot reach the leaves of the seedling.

If the LED grows light is placed further than 27 inches away, it will not provide enough light for proper growth. In addition, photosynthesis will only occur if an intense amount of blue and red-light waves is emitted towards the plant, which would likely damage its leaves.

In summary, seedlings should be 18 inches to 27 inches from a grow light. Seedlings that are too close will not have enough oxygen and can suffer damage to their leaves. Seedlings that are too far away will also lack the necessary levels of photosynthesis needed for healthy growth.”

Why Are Some Plants More Sensitive to Heat Than Others?

Just like people, some plants are more sensitive to heat and sunlight than others. A plant’s sensitivity is closely related to its evolutionary development.

Plants developed in arid conditions may be less prone to damage from high temperatures because they evolved with drought-like environments. Conversely, some plants may be more prone to heat damage simply because they prefer the warmth of hot climates and will grow better under these conditions as well.”

When Should You Start Worrying About Your Plant Getting Too Hot?

It would help if you started worrying about your plant getting too hot when the temperature reaches 85 degrees Fahrenheit. Generally, a temperature of around 80 degrees is a safe range for plants, but temperatures that rise above 85 degrees will quickly start to take a toll on your plants.

 The plant’s leaves may scorch or turn brown under these conditions, and they could eventually die due to heat damage. If you notice any signs of this happening, take steps as soon as possible to cool down the temperature around your plant.”

For seedlings, part of the danger of too much heat is its effect on the water and oxygen supply. Excessively hot conditions will cause the humidity to drop and air circulation to slow down. This leads to a lack of water for the plant as well as an increase in carbon dioxide levels that suffocate it.”

Is It Ever Okay to Leave Your Grow Lights on All Day Long, Even If the Temperature Is Already High Enough in Your House or Apartment?

How Far Should Seedlings Be from a Grow Light

It’s never okay to leave you to grow lights on all day long. It may seem like a good idea because the light emits stronger wavelengths, and it will probably make your plants grow quicker, but this practice actually has serious consequences. Leaving lights on too long can cause the temperature to get hotter than you want it in your house or apartment due to the heat generated by the lights themselves.”

If at any point you notice that one of your seedlings is starting to wither or turn brown due to prolonged exposure, it’s time for you to take action.”

“You should first stop using lamps if they’re not necessary, remove other objects in the room that are blocking airflow, and move any plants closer to a window.”


After reading this article, you should answer the question of how far seedlings should be from a grow light.

When thinking about where your plants will live in their first few weeks or months, it’s important that they get enough light but not too much.

We recommend that plants under fluorescent lights and other artificial lighting sources have at least 18 inches between them, with no more than 3 feet optimal for good results.

Peter K. Vail
Peter K. Vail holds a BS in Horticulture. His professional background includes roles in agricultural research and urban farming initiatives, bringing over 14 years of experience to our readers. Peter’s approach to writing is deeply rooted in scientific evidence while remaining accessible to gardeners of all levels. In his free time, Peter enjoys rock climbing and participating in community gardening programs, always seeking new ways to apply his expertise.

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