How to Use LED Grow Lights

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LED Grow lights are a breakthrough innovation helping people grow plants indoors. These lights provide sun-like lights to plants; therefore, helping in their growth. Both hobbyist plant growers and commercial users employ them to ensure the optimal development of their crops. Nevertheless, for several people, it is a new thing. They do not know how to use LED Grow lights properly. 

Undoubtedly, using plant-growing lights is straightforward. However, there are plenty of things to keep in mind. For example, understanding the color spectrum of light. Analyzing the suitable distance of plants from Grow lights during the different growth stages, and so on. Additionally, you have to take care of the maintenance and safety of your grow lights.

Let us discuss the different aspects of using LED Grow lights in the right way so that your plants can get the utmost growth.

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If you want to know how to use LED Grow lights for indoor plants specifically, we recommend checking out another blog, i.e., How to Use LED Grow Lights for Indoor Plants》.

Choose Quality LED Grow Lights

The first and foremost thing you have to pay attention to is the quality of your LED Grow lights. While there is no shortage of companies making plant-growing lights, not all have the same quality and performance. Therefore, choose an experienced and reputable LED Grow Light manufacturer

When choosing plant growing lights, check for warranty, heat sink, and quality testing certificates, such as CE, UL, TUV, EPA, ROHS, etc. Never invest in an inferior plant growing light as it might affect the photosynthesis process badly. It is the process by which plants convert light into chemical energy. This energy is crucial to plant growth. 

Wondering how to source better LED Grow Lights? Read all the details on 《Top 11 Things to Consider When Purchasing LED Grow Lights.

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Consider Your Requirements for LED Grow Lights

There is no doubt about it that you have to choose a quality plant growing light. However, it should be as per your needs as well. 

Consider your requirements first. Are you a hobbyist plant grower? Do you have a large greenhouse where you grow plants for commercial purposes? How much growing space do you have? What kind of plants do you grow? 

Answers to these questions will help you select the right LED grow lights. Discuss your requirements with your potential LED Grow Supplier so that they can provide you with appropriate lights.

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Understand the Color Spectrum of Grow Lights

If you want to make the best use of grow lights, understand their color spectrum first. It will help you make sensible assumptions about your crop growth.

Like the Sun, plant growing lights emit a full spectrum of light that contains all the crucial hues and colors required for plants’ growth during different cycles.

Some important hues/colors in the light spectrum are as per below.

Blue Light

During the early stage, plants absorb blue light to thrive. It helps in root development and provides better nutrition to plants.

Purple Light

Like Blue light, it helps during the vegetative stage. Nonetheless, it is not as effective as blue light for photosynthesis.

Red Light

Red light helps plants during the development stages, especially during the budding of flowers. The chlorophyll pigments of plants absorb this light too much. As a result, it supports photosynthesis. Furthermore, Red light provides better biomass growth and stretching to plants.

Plants react differently to different colors in the spectrum from the propagation until they become adults.

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Appropriate Distance of Grow Lights from Plants During Distinct Growth Cycle

Once you have chosen appropriate grow lights, your next step should be setting them up properly. Your plants require different light intensities during distinct stages. Hang them above your plants and adjust the height of lights as per the plants’ growth.

PAR (Photosynthetically Active Radiation) is the parameter to measure the intensity of plant growing light. It generally measures the amount of lights plants absorb in the Photosynthesis process.

Let us take the example of PAR intensity cannabis required during a distinct growth cycle. It will give you an idea at what distance you should mount your LED grow lights. 

Note: If you are looking for more knowledge about LED Grow Cannabis Lights particularly, check out our post: 《9 Things You Need To Know About Led Grow Cannabis Lights》. 

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It is the initial phase when you place Cannabis in soil for propagation. At this phase, the growth of the plant must be vital. Mount your LED grow light a few inches above plants to provide the maximum light. Hang them 24 to 36 inches above the canopy during this stage. Also, provide at least 14 hours of lights to your plant.

During the propagation period, Cannabis generally requires between 150-200 μmol/m2/s. Check the specification of your light as different LED grow light models have distinct wattage specifications.

Vegetative Growth Phase

It takes around two to three weeks to establish roots. Afterward, your plants began to sprout leaves. Now you have to move your light 12 to 24 inches away from the canopy. During this stage, the light requirement for your plants might increase up to 550μmol/m2/s. Consequently, keep your LED grow lights on for 18+ hours. 


It is a budding phase of cannabis. Throughout this phase, they need light between 500-700 μmol/m2/s. Provide 12 hours of lights for three to seven days.

Flowering Stage

Depending on the strain of Cannabis, the flowering phase may go from eight to eleven weeks. Since the height of plants will increase a little more, you will need to adjust the height of lights moderately. Hang them a few inches above the canopy. Make sure Cannabis is not struggling to get light. They require light of 700-800 μmol/m2/s. Keep the grow lights on for at 12hours for eight to ten weeks. Also, keep your grow lights 18 to 24 inches above plants.

Expose your cannabis plants to grow lights for recommended hours. 

Remember, keeping lights on all day long would not work as well. Your plants also require some dark time to rest.

At Darkless LED, we have advanced LED grow lights that come with adjustable brightness. You can customize the intensity of light at various growing phases.

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Watering & Feeding of Plants When Using LED Grow Lights

While plants get similar energy under grow lights as they get under the Sun, there is a difference in the environment. 

Growing plants in the open air and under the Sun is different from growing plants inside a greenhouse and under the plant growing lights. As a result, you must water your plants less often as water might take some time to dry out. 

Depending on the plant type and weather conditions, sometimes the situation could be the opposite. It generally happens in the summer.

Since LED grow lights are potent, their direct light may dry out the soil fast. So you have to keep both situations in mind when planning the watering schedule for your plants. Test your soil for moisture and dryness with your finger before watering it.  

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Hanging of LED Grow Lights

Make arrangements for hanging LED grow lights. Depending on the space and plants, you can build the shelving units. Not only will it keep your floor clean but also you can attach lights easily. 

You may use an S-hook, wire, and chain to hang lights above plants. Nowadays, adjustable hanging ropes are readily available in the market. Make sure the shelving units are of high quality and do not erode from dirt and water quickly.

Use a Timer

Plants grow properly when you provide them with consistent light every day. Even cannabis requires a consistent light in every growth cycle. To ensure this, you can invest in a timer. It will help you provide the appropriate light to plants regularly.

Don’t give plants light for 14 hours one day, and then 20 hours the following.

Prevent Excessive Heat in Growing Area

No matter, if you are growing plants indoors or in a greenhouse, you need to ensure the proper air circulation in the growing area. 

Poor air circulation can lead to various plant diseases caused by humidity.  Make sure your LED grow lights do not produce too much heat and have a proper heat-emitting system. Besides this, make proper vents in your growing area. Check out if you need a fan to circulate heat.

Safety and Maintenance of LED Grow Lights

Using LED Grow lights properly is not enough; you must ensure their safety and provide them maintenance from time to time. 

Clean them frequently to remove dust and dirt from them. Otherwise, they will emit less light while consuming the same energy.

You can use a moist cloth to clean the light’s exterior. Use a small amount of water only. To clean cables of the lights, use alcohol swabs. Do not let your LED grow lights come into contact with water. It might cause hydroelectric contact and result in a short circuit. To learn more about avoiding mistakes in use, check out this article from us:Using LED Grow Lights: 9 Mistakes to Avoid

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