Grow Light Distance Chart Guide

Growing plants indoors requires precise light placement. For plants to grow at a healthy rate, they must receive enough energy. Your plants will likely be damaged if the light is placed too close or too far away from them.

So, where exactly should you put your grow lights for maximum efficiency?

It's difficult to answer this question as growers utilize various types and sources of light. Nevertheless, most modern indoor grow setups use LED (light-emitting diode) lighting.

In this article, we'll explain how far grow lights should be from plants in your indoor grow setup with our in-depth grow light distance chart guide.

Types of Grow Lights and their Distance Charts

You most likely found a bunch of different answers when you searched for the right distance to hang your grow lights. Sadly, there is no exact measurement. There is a wide variety of grow lights you can use for your indoor grow setup, and each of them has different characteristics and applications.

Unlike standard fluorescent grow lights like CFLs, the HPS and LED bulbs can produce so much light that they can overwhelm your plants. To achieve the best results with LED and HPS grow lights, these lights must be used in the proper way!

It is impossible to give a precise answer to determining the perfect hanging height because so many factors are involved. No matter what your lighting setup, this guide will show you how far away to keep your light, so you get amazing results every time!

If you'd like to know more about the relationship between a plant's life cycle and grow lights, check out our article discussing how far grow lights should be from plants.

LED Grow Light Distance Chart

In most cases, people who have indoor gardens choose LED lights for their grow setups. Besides heat and light exposure, LED lights are also very convenient because their spectrum has a wide range of colors.

Even so, many people wonder what the correct distance between a grow light and a plant is. There are many factors to consider when answering this question, but in general, a good distance should be 40-66cm for low-powered LED lights, 50-75cm for medium-powered LED lights and at least one meter for LED lights that exceed 900W of power.

Below, we've provided a detailed chart of how to gauge LED distance from your plants:

A 600W LED grow light is shown in the chart above at various distances from the plant canopy. 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. PPFD/PAR changes with the distance of the plant canopy from the light source. The chart also shows how a plant's canopy coverage changes with distance from a 600-watt LED light.

For a more detailed explanation and guide on how to use LED grow lights, click here!

CFL Grow Light Distance Chart

Originally, CFLs were designed to replace incandescent lamps. CFLs have a lifespan of up to 10 times longer than incandescent bulbs and even produce less heat. In addition, incandescent bulbs consume less power than LEDs to produce the same amount of lumens. For gardening, soft white and daylight CFLs are the most effective and commonly used types of bulbs.

Color temperature is the biggest difference between these two bulbs, measured in K (degrees Kelvin). It is extremely important to consider color temperature when using CFLs to grow plants since different phases of plant growth require different light temperatures. Therefore, whenever you are growing with CFLs, you should always use a combination of both kinds of bulbs.

Below, we've provided a detailed chart of how to gauge CFL grow light distance from your plants by the strength of the CFL bulb and phase of the plant's life cycle:

HPS Grow Light Distance Chart

HPS (High-Pressure Sodium) lights are the most widely-used and highest-yielding grow lights for growing indoors. The light they emit helps plants grow taller and produce larger crops during both the vegetative and flowering stages of plant growth.

To ensure the healthy growth of seedlings, growers need to keep HPS away from their seedlings due to its potential to produce high amounts of heat. Your plants can suffer damage if your grow light is too far away from them. Additionally, plants can stretch, which is when they grow taller to reach the light source closest to them.

It is generally recommended to keep HPS a distance of between 10 and 14 inches from seedlings. Depending on the HPS wattage, seedlings may need a different distance from an HPS light. A distance of 5 feet is likely needed for 1000-watt HPS lights.

HPS lights are available in many different types and wattages, so we have created a chart that illustrates the distance you should keep between HPS lights and plants depending on the types:

Why is it Important to Measure the Grow Light Distance?

Growing plants at home isn't for everyone. For some, their plants wither quickly or they produce no crops at all. These problems can be attributed to improper lighting. Grow lights can harm plants and make the growing process more inefficient when used incorrectly.

Plants need light to thrive. For photosynthesis to occur, plants need light to convert light, oxygen, and water into carbohydrates (energy). Energy is essential to the growth, blooming, and seed production of plants. However, if the distance between the grow light and the plant is too close or too far, the plant will suffer.

It should also be mentioned that too much light is incredibly harmful to plants. When exposed to too much light, plants often display symptoms of distress, regardless of their growth stage. When the grow lights are too close to the canopy of the plants, they may also become discolored or stunted in their growth. The grow lights must be adjusted immediately in both cases.

What is PPFD and How to Measure it?

As we’ve mentioned in the charts above, measuring PPFD is crucial for the health and well-being of your indoor plants. PPFD, or photosynthetic photon flux density, is the number of photons that cover a square meter per second. In other words, it is designed to measure the amount of photosynthesis-active radiation (PAR) available to plants.

The PPFD unit is measured in micromoles (one micromole equals 62 quadrillion photons) per square meter per second (µmol/m2/s). For indoor cultivation spaces, the ideal PPFD levels are 700-900 mol (PPFD), and there should not be any spots with a PPFD below 500 mol (PPFD).

Are LED Lights Good for Indoor Plants?

LED grow lights can be used to grow plants indoors. LED (light-emitting diode) lighting is common in modern indoor grow setups. LED lights are a cost-effective, energy-efficient, and customer-friendly alternative to fluorescent lights and incandescent lights for growing plants at home. LED lights emit low heat, use less power, and can be color spectrum matched to the growth of your plants.

Correctly used LED grow lights can produce great yields. However, the main downside to using LED grow lights is that they don't produce much heat, which is crucial for the successful lifecycle of any plant. Furthermore, it's always difficult to measure the correct distance between your LEDs and plants.

Even so, LED grow lights are extremely efficient for indoor growing, and with a little bit of knowledge, can yield you the best results! Check out our guide on LED distance for growing setups for more information!

Things to Avoid when Installing Grow Lights

Here are five things you should consider when installing LED grow lights to avoid damaging plants and other unnecessary problems:

• Grow Light Distance - Putting the lights too close or too far from the plants could cause the plants to overheat or be underlit. A distance of 12 to 18 inches is recommended between the LEDs and the plants. A universal rule, however, does not exist for determining the distance.
• Wrong Light Schedule - Lighting your plants 24 hours a day can damage them. Most plants require between 18 and 24 hours of light during their vegetative stage, but when they flower, the number of hours decreases. You have to get the lighting schedule right for your indoor plants to grow and thrive.
• Wrong Light Spectrum - Different plants require different spectrums of light. Lighting plants incorrectly can adversely affect their growth. LED lights come in full-spectrum versions, so you can adjust them to meet your needs. Nevertheless, if you set it incorrectly, your plants may not develop. For example, plants in their vegetative stage grow best under blue spectrum lights but are damaged under the red spectrum.
• Overheating - Too much heat will cause the plants closest to the light to turn brown. The moment you spot thin outlines on the leaves, you'll have to prevent further damage by distancing the light from the plants. A plant with curled leaves could also be too close to the light.

Wrap Up!

In today's indoor growing industry, we can use a wide range of light bulbs and techniques to get the best yields out of our plants. However, it is crucial to understand what our plants need. We also understand that the available space for your grow setups differs, so set up your lights according to our guide here!

Correctly distancing your indoor plants from your grow lights is one of the most important factors to indoor growing. Plants that receive too much light or too little light will either grow poorly or die! Be sure to take a close look at the distance charts above to ensure a healthy life cycle for your plants.