Can grow light burn my plants?

Last Updated on January 18, 2021 by cmoarz

Yes, But there is more to it!

Light is one of the most crucial factors to growing plants, but the question that needs to be considered is whether grow lights can burn plants and how much light could be too much?

Light (even intense light) won’t burn your plants in most cases. But like with most things in life, there are exceptions to the general rule. Modern grow lights can produce extremely high levels of light that can cause photo-bleaching and the leaves to burn.

Another challenge you could be facing while using grow light for your plants is that there are some species that prefer indirect light as opposed to being exposed to a direct source of light all the time, so you want to make sure to know your plants well. No matter how much care and attention you give to them, they aren’t going to develop properly if you don’t know and meet their specific needs.

Is your plant getting too much light?

Checking if your light levels are too high is a pretty simple task. If your plant is getting too much, it will let you know by:

Folding up

burned spots may show up

the color will start to fade in the leafs.

What type of grow light to choose for plants?

Not all grow lights have the same heat and usually, it’s the heat that burns plants. Some lights, like fluorescent, incandescent, and HID lights have bulbs that can get quite hot and these lights can basically cook your plants (especially if they’re too close to the plants.)

Of all the mentioned light types, choosing specialized LED grow lights are the best choice you can make. Although LED grow lights also produce some heat, they deal with the heat more effectively and you can expose your plants much closer to LEDs that other types of lighting.

If you’re new in the plant-growing world, you may not be familiar with the fact that there is an important difference between regular LED lights (which are relatively cheaper) and LED grow lights. In general, you could use the regular LED light, but it won’t ensure your plants to grow healthy and efficiently, as regular LED light doesn’t contain enough colors and light spectrum. If you want to grow your plants indoors, where they won’t be exposed to regular sunlight, it’s better to buy specialized LED grow lights.

Full spectrum grow light chart

The right light intensity

The right intensity of light that a plants receives is determined by two factors, the brightness of the bulb and how close the plant is to the light source. 

This mostly depends on the type of plant, but you should keep in mind that a PPFD of 800 is enough to ruin plants that are more sensitive. Typically, those plants that are native to shady forests or the tropical jungle don’t require as much light as plants that evolved in dry climates (like for example in the Mediterranean or southern Mexico).

Flowering houseplants, such as begonias will require to stay at least 10 to 12 inches away from the light source to thrive, while foliage plants, such as philodendron or ivy, should be placed around 36 inches away from the grow light. Still, there are many plants (gardenias, citrus, orchids, and most vegetable plants) that will require a much higher light intensity.

This means that you will need to take some time to divide your plants by their needs and that you won’t be able to place different types of plants under the same grow light. Make sure to combine the plants that are happy with the same distance and the power of the lighting. Give your plants time to rest

No matter what types of plants you are growing, all of them need a proper rest. Just like humans need sleep to gain their energy back, plants cells respire even when it’s dark which is as important for the grow process as sunlight.

When it comes to the preferred number of hours of light for plants, botanists usually divide the plants into three main categories:

  • long day plants (require 14 to 18 hours of light per day):

Examples: hibiscus, coneflower, lettuce, spinach, radish, sugar beet and most seeding for vegetables and garden flowers

  • short-day plants (require less than 12 hours of light per day)

Examples: chrysanthemum, rice, soybean, onion, violet, Christmas cactus, and poinsettia

  • day-neutral plants (require 8 – 12 hours of light all year round)

Examples: sunflower, tomatoes, roses, foliage plants, geraniums, and African violets

If you’re usually forgetful, you could think about building a power strip with a timer that will do the work for you and will control the duration automatically. And once you set your plants in the right place and give them enough light and some time to rest, you’ll soon be able to enjoy the first seeds of your own plant-based paradise.

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