How Grow Lights Work

Do you want to embark on growing plants inside of your home? In this article, we talk about how lights work and how they can affect plant growth. We’ll also discuss some of the pros and cons of LED grow lights.

Why Do Plants Need Light in the First Place?

Before we look into what LED grow lights are and how they work, let’s first consider the benefits of light in the first place. Why exactly do plants need light to grow? Well, everything needs the energy to grow. Humans get that from food, and plants get their energy from light through photosynthesis. So without being exposed to light, plants won’t be able to grow and will die.

However, this doesn’t mean that any lights work for growing plants. Instead, we refer to plants as requiring a light spectrum, as they are affected by the colour of light on this spectrum. For example, fluorescent grow lights contain blue light, which helps give your plant the light it needs. However, halogen and incandescent options provide red light, which isn’t beneficial to your plants’ development.

So, when plants experience low light levels or don’t get enough light, they can encounter several problems. These often include changes such as the stems becoming stretched out (because the plant is trying to reach light), the leaves turning yellow, and you might discover brown edges on the leaves. In addition, the leaves might dry up altogether.

What Are LED Grow Lights?

LED grow lights are bulbs with LED chips that produce the spectrum of light that plants need to grow. They’re available in various sizes, shapes, and power levels, where the quality of the LED chips determines the bulb’s effectiveness. But, before you purchase any grow lights for your indoor plants, you must be aware of the type and colour of lighting your plants needs.

To break it down, let’s look at what LEDs are and what they do. LEDs are small components comprised of different types of semiconductor material. When the voltage is added to the LED, the electrical current starts flowing, releasing energy in light.

How Does LED Grow Lights Effect Plant Growth?

LED lights can have a host of influencing factors in a plant’s development and flower formation cycle. For example, by adding colours to the light spectrum, you can influence different types of growth, such as leafy lettuce or juicy tomatoes. In particular, common lights include blue and red. However, you can purchase LED lights that contain a large spectrum of colours, which might not always be beneficial for plant growth but can promote plant health and reduce any browning or drying leaves.

The Pros and Cons of Using LED Grow Lights

For you to have a complete understanding of why one should use LED grow lights and in which situations they may not be necessary, here are some insights into the pros and cons of light-emitting diodes.


Here are the pros of using LED lights at home.

Cool Temperatures

One great benefit of LED grow lights is that they don’t emit a large amount of heat like other lighting systems. This means that the lights won’t negatively affect the temperature in your room, so you needn’t place your plants in an isolated room purely because of the lights’ potential temperature release.

Full-Spectrum LED

Full-spectrum LED lights provide a large range of colours from the bulb to give you all the light that your plants need for optimal growth. Additionally, most full-spectrum LED grow lights produce the exact amount of light required for each plant growth stage. As a result, a full-spectrum light system can be more beneficial than direct sunlight.

Environmentally Friendly

Unlike high-intensity discharge (HID) lights, LED grow lights are 100% recyclable and don’t contain any toxic substances, such as mercury.

Target Wavelength

LED grow lights allow you to give plants the exact amount of light it needs for photosynthesis, as you can regulate the wavelengths of light. With LED lights, you can provide your plants with all the light they need to grow efficiently.

Healthy Plants

Most importantly, you want your plants to grow healthier, and fortunately, LED lights to allow this to happen since they don’t emit UV or IR rays and heat. Moreover, any harmful wavelengths are limited to encourage healthier plants, which is particularly important for vegetation.


Below are some considerations to bear in mind for newbie indoor growers.


Although LED grow lights have a long lifespan, they won’t last forever. LEDs might begin to change colour as the lights grow older. As a result, this colour change could contribute to poorer quality lighting. However, you can prevent this effect by obtaining high-quality LED chips with lights purchased from a reputable supplier.

Temperature Sensitivity

We mentioned earlier that grow lights don’t emit large amounts of heat during use. However, they are sensitive to temperatures and may require a fan system to help with temperature regulation.

Costly Upfront Price

For the best LED grow lights, you may need a big upfront sum of money. You can purchase LED lights for less than $50, but we recommend opting for higher quality products where you will often find that the cost price may lie around $100 and more.

Limited Directional Lighting

We all know that LED grow lights only provide light to a limited area. In addition, it is typically smaller than conventional lighting systems. Therefore, you might need to make manual adjustments as the plants progress through different growth stages. Or, another option is to purchase several LED grow lights to ensure that all plants have enough light.

How Long Should You Leave Grow Lights on For?

The number of hours of light exposure depends on several factors, such as the type of light you use, your environment, and the type of plant you’re trying to grow.

So your plants grow healthily, we recommend using LED grow lights for around eight to ten hours a day, but this can also extend up to 16 hours in some circumstances. Fortunately, this type of light is energy efficient, so you don’t need to worry about the energy bill of having the lights on all day.

Position your grow lights just above the plants to replicate sunlight and allow the plants to lean towards the light source naturally. However, ensure that the grow lights are not too close to the plants as this can be damaging or brown their leaves. You should also bear in mind that different plants require a different amount of light. For example, plants with large leaves will absorb more light than smaller plants.

How Many LED Bulbs Will You Need?

If you’ve never used grow lights before, you might be wondering how many bulbs you need to help your plants grow. For indoor growing, the objective should be to surround your plants with as much light as possible. When plants are growing inside, they’re not exposed to the same light intensity as when outdoors. For this reason, you need to increase the light output. For indoor growth, this may mean that you’ll need to emulate the sun’s movement across the sky by having a source of light on all areas of the plant.

Let’s say you use only one LED light on several plants. This idea won’t necessarily help your plant’s growth since only a portion of the plant receives the light it needs. Instead, we recommend using three to four bulbs for your indoor garden, depending on the size and number of plants you have. You can even add mirrors to your setup to reflect the light onto the plants’ leaves to support even more lighting. This is also a cost-effective solution if you’re concerned about the cost of grow lamps.

LED Grow Lights Compared to Metal Halide Lights

Compared to an LED grow light, a metal halide grow light has a longer warm-up period and a reduced lifespan but provides high-quality lighting. Moreover, they’re some of the most energy-efficient types of grow lights emitting cool colours. Plus, plants that colour under these LEDs receive the essential wavelengths for optimal growth since they’ll receive a complete light spectrum.

What Efficiency Tips Do You Have on How LED Grow Lights Work?

If you’ve used LED grow lights before and have more knowledge on how grow lights work, share your tips and recommendations in the comments below to inspire other indoor gardening enthusiasts.

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