The Best Kelvin for Growing Plants LED – Revealed!

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Last Updated on February 27, 2023

Selecting the best Kelvin for growing plants LED for your plants’ growing needs is one essential factor in an indoor garden. As we know, grow lights mimic the light provided by natural sunlight and this must be done in the presence of the correct light temperatures.

Your plants will flourish when they are exposed to the appropriate light temperatures so this is why you must ensure that you get it right. So, if you are wondering how to go about the best light temperature for your growing plants, we’ve got you covered.

We are all about easy indoor gardening. So, by the end of this article, you should have an idea of the right color temperature for each of your plant growth stages and more.

What is a Grow Light Color Temp?

Grow light color temperature is the accurate light spectrum provided by a grow light and is required for each plant growth stage. It is a means of showing the appearance of the light which is supplied by a light bulb. It is essential for a grow light to contain the necessary spectrum so a plant can grow healthily and adequately.

Light is known as electromagnetic energy which is measured in wavelength. This wavelength can be seen in various visible light colors waves that vary from red, blue, and yellow, to green. Blue and red light are the colors mostly absorbed by plants for the photosynthesis process.

What Is A Grow Light Color Temp

The color of light supplied by a particular grow light is known as color temperature and is measured in Kelvin (K). The Kelvin has a scale that ranges from 1,000 (warm or red) to 10,000 (cool or blue).

Kelvin color temperature scale

Grow light Kelvin rating or scale is a measurement of color temperature and it’s used to explain how different light temperature appears. Practically every light that comes with bulbs will be associated with Kelvin color temperature.

You must be enlightened on the various color temperature as this will help you in deciding the best lighting for your plants’ needs.

The Kelvin scale figures at the lower end offer hues of red. While on the other end, the Kelvin scale where the figure goes higher, it offers hues of blue.

Spectrums with low Kelvin ratings (around 2000K to 3000K) are also described as warm, while those with higher ratings (5000K or higher) are often referred to as cool.

Why is Grow Lights Color Temperature Important?

The importance of growing light color temperature cannot be overemphasized. It has a great impact on the growth of plants.

Take, for instance, blue light is essential for vegetative growth. On the other hand, red light is required for the flowering stage and fruit production. Therefore, the color temperature will assist in deciding the best light temperature for your plant’s growing needs.

EZORKAS 9 Dimmable Levels Grow Light with 3 Modes Timing Function for Indoor Plants

Light Spectrum Pigments

Plants contain various pigments they use in absorbing or reflecting certain light wavelengths. These pigments are used in the process of photosynthesis whereby plants make use of light energy to produce their food.

So, let’s take a look at two (chlorophyll and carotenoid) of these pigments involved in photosynthesis:

  • Chlorophyll: the green pigment contained in plants that allows them to manufacture their food is chlorophyll. It is the most abundant pigment found in plants, and chlorophyll A is responsible for the absorption of light energy.
  • Carotenoid: the second most important pigment is the carotenoid. Carotenoids also help plants take in light energy, which in turn, transfers the energy to chlorophyll.

The Best Grow Light Color Temperature For Growing Plants

Choosing the right color temperature for the various stages of your plants can be determined by the values on the Kelvin scale.

Also, different grow lights are configured in various ways. Some grow lights offer a full spectrum for your plants and will not require you to switch lights for different plant stages. Examples of such grow lights are LED lights.

While some grow lights are not configured to be full spectrum. Thus, you will be required to switch these lights as your plant enters its different growth stages. Examples of such grow lights are traditional lights such as fluorescent, HID, and so on.

The Best Grow Light Color Temperature For Growing Plants

Most of the LED grow lights have been we have in the market are configured with full spectrum. Therefore, you can use the same light for all your plant growth stages. The only thing you need to do is position the LED to grow lights distance to your plants’ canopy appropriately as they enter different growth stages.

So, let’s look at the required or best light temperature for your growing plants in their different growth stages:

1.    Best kelvin for seedlings and clones

The best color temperature for seedlings and clones is the blue spectrum. If you’re using the traditional grow lights, choose daylight bulbs that fall on the higher end of the Kelvin scale. Use 5,000 and above Kelvin figure bulbs for your seedlings.

We recommend you use fluorescent bulbs for seedlings and clones because they don’t produce too much heat. The clone and seedling stages are the most fragile, and therefore need to be handled with care.

Other traditional lights such as the HID may also be used for your seedlings and clones. However, they produce a lot of heat. So you need to be extremely careful so they don’t burn your fragile plants.

2.    Best kelvin for the vegetative stage for rowing plants

The vegetative stage of a plant also requires blue lights which are at the higher end of the Kelvin scale. Just like seedlings and clones, vegetative growth should use bulbs ranging from 5,000 to 7,500 on the Kelvin scale. However, the lighting needs to be more intense for vegetative growth.

3.    Flowering and fruiting stage for growing plants

For the flowering and fruiting stage, your plant will require the red light spectrum which is at the lower end of the Kelvin scale. This light spectrum will encourage flowering, blooming, and fruiting.

Use light bulbs that range from 2,000 to 3,000 Kelvin values. HID lights such as high-pressure sodium (HPS) offer more of this red light spectrum. You can also use the LED full light spectrum for all plant stages.

Is Warm Light Good for Plants?

When shopping for grow lights, you will notice that they are labeled with numbers such as 2700K or 4000K. These numbers refer to the relative warmth or coolness of the light on the color spectrum. The higher the number, the cooler the light.

The growth of plant foliage is usually best around 6500k. However, they still need a period of warmer light of around 3000K to produce flowers, and eventually fruit. 

So is warm light good for plants? The answer to this question depends on what you ultimately want to produce with your plants. If your goal is to produce seedlings, leafy green vegetables, or root crops, you need higher spectrum bulbs, which are the cooler light colors. But if you want to produce flowers, such as in the case with marijuana, or any other fruiting plants such as cucumbers, tomatoes, peppers, and lemons, you will require warm light which is in the lower spectrum. Warm white light is better and stronger on the red end of the spectrum.

Because lights require different lights for the different growth stages, it might be best if it gets a full spectrum LED, so you will not have to worry about switching lights as your plant progress.

3000K vs 5000K Grow Light

Both the 3000K and 5000K grow lights are in the white light spectrum. The difference is that 3000K is a warm white, whereas 5000K is a cool white.

A 3000K grow light bulb produces a soft white light which can also appear yellowish. One of the best uses for this light is in the bedroom as it gives a relaxing mood. For plants, a 3000K grow light is required for flowering, and thus fruit. 3000K is more efficient for flowering when counting grams per watt.

A 5000K grow light is ideal for plants in the vegetative stage of growth. The big advantage of this grow light is that it will help your plants to produce tighter internodes which will give you a more balanced distribution of light over the colas later.

Plant Light Requirements Chart

Different plants have different light requirements. Light is required by plants to produce chlorophyll for energy through photosynthesis. If they do not receive enough light, they will end up weak and pale. If a plant is overwatered, its roots will not grow enough to absorb the moisture. 

To determine how much light your plant is receiving in the environment it is, there is a simple test you can use called the shadow test. This works especially well for indoor plants. Follow these steps to do so:

  1. Get a large, blank piece of paper. 
  2. At the brightest time of the day, place the paper vertically and facing the light source, at the precise height and location you would like to place your plant. 
  3. Place your hand a few inches away from the paper.
  4. Use the Light Requirement Chart (below) to determine the type of lighting that your plant will be receiving

Conclusion – The Best Kelvin for Growing Plants LED 

This article has shown us that light temperatures are essential for plant development. It has also shown that there are suitable Kelvin ranges for the different growth stages that plants go through. It is important to make sure that you stick to the relevant Kelvins at the appropriate growth stage to get the best out of your grow lights and your plants.

Using the right Kelvin for your growing plants will also help you save costs. We hope this information will be of great help to you and your plants on your growing journey.

Happy growing!


Is Warm light or cool light better for plants?

In the case of growing houseplants, you should be aiming to use cool light. Cool light comes from a combination of the sun and air conditioning. The sun produces light that is predominantly yellow-orange, with a very slight blue tinge, and the air conditioning adds red and far-red wavelengths.

Cool light is best for plants because it mimics sunlight, which they need to grow. The sun produces both warm light and cool light. Warm light is a combination of both blue and yellow wavelengths. Q: Do you know how to grow indoor plants in winter? A: Yes. You can grow houseplants i

Is 5000 Kelvin good for plants?

Yes, 5000K is enough for most plants. But don't use 5000K as the maximum. You can get some plants that flower really well under 2000K, such as geraniums and some begonias. There are many other plants that need a higher light spectrum. If you want to grow plants indoors, then your best bet is to set your LED to about 5500K, but not at full power. If you do this, then you can turn the lights off for 4-8 hours at night, which will give you enough light to get by without turning on the lights. Then you'll have a nice light spectrum in the middle of the day.

Will LED lights help plants grow?

One of the biggest questions that people have about growing plants indoors is whether it's possible to grow plants in an LED light. The short answer is yes, you can, but there are some things to consider before you make the switch. 

It's not as simple as just putting a plant in an LED light and leaving it there all day, because not all LEDs produce the same amount of light. A lot depends on the type of LED bulb used, the wattage and the number of bulbs used. There's also the matter of how far away your plants are from the bulbs.

Does regular LED light help plants grow?

These lights have different wavelengths that affect plant growth. Red light stimulates photosynthesis. Blue light promotes cell division. White light is a mixture of red and blue. Now, we can use all three colors together to create the spectrum of light. There are many types of LED lights. The most common type is the LED strip. It has red, blue, and white LEDs. We can also put them in groups. For example, we can use a single red LED on one side of the plant and a single white LED on the other. This will make it easier to grow plants.

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