What Color Light is Best for Plant Growth?

by Kevin

Plants can't see a thing, but that doesn't mean they're color blind. Find out why your indoor gardening grow light hydroponics system needs to have a varied array of color temperatures.

Simply having a powerful indoor gardening grow light hydroponics system is not enough these days, especially if you want to get the most out of your plants. Regardless of what you're growing, in order for it to grow at its full size, you'll want to give your plant the best humidity, temperature, nutritional and lighting conditions.

Varied Color Temperatures in Indoor Grow Light Hydroponics

What is The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics?

The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics
The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics


It's the latter that I want to talk about in this article, since proper lighting is often overlooked by inexperienced hydroponic gardeners.

As you probably know, light is composed out of a spectrum of "color temperatures", from red to violet. During or after a rain, a rainbow might appear on the sky due to the fact that water particles in the air get pierced by light particles and the light decomposes into these 7 primary colors: Red, Orange, Yellow, Green, Blue, Indigo and Violet.

In many cases, we cannot detect the exact color temperature of a source of light, but plants have a very keen sense to this. Naturally, plants will benefit most from color temperatures of red and blue, that's why more and more indoor gardening grow light hydroponics systems focus on creating a combination of the two.

In Conjunction with the Natural Sunlight

In hydroponic greenhouses, a light system is used in conjunction with the natural sunlight that comes through the glass, but indoors, your plants will rely solely on the artificial lighting you provide them with.

The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics
The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics

During the growth phase of your plants, you will want to provide them with a combination of blue and red color temperature lights. Since the most common and effective indoor gardening grow light hydroponic systems today are based on metal halide and high pressure sodium, you can try getting both types of lights, or a system that lets you switch between the two.

Blue Lights on Growth

Metal halide lamps have a bluish tinge and this blue light gets absorbed by a plant's chloroplast, which feeds the rest of the plant, allowing leaves and flowers to expand better. I found a very nice piece of research material regarding the effects of blue lights on growth here, but I have to warn you, it's a scientific article and terms might get heavy at times.

The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics
The Importance of Varied Color Temperatures in Indoor Gardening Grow Light Hydroponics

Indoor gardening grow light hydroponics systems that shine red also have a positive effect on plant growth. However, the growth effects from red light are different than with blue light. Whereas growth using blue light colors had the purpose of feeding and developing the plant, red light is used as a competition edge.

Yes, plants compete against each other and they do so with the help of red light colors. If there are a lot of other plants around a particular one, it will receive red light reflections from all angles, notifying the plant that competition is stiff and it will need to grow taller and wider in order to survive in this environment and not get overshadowed.

So artificially using red light to grow plants, you can basically trick the plant into thinking it needs to grow taller and bigger, because there's a lot of competition around it.

High pressure sodium hydroponic lights have a distinct orange or red shine, so they're probably best for this job, but led lights are also useful in many cases.

Plants with Different Color Temperature Preferences

Obviously, different plants have different color temperature preferences. Plants that naturally grow in less bright conditions, such as forest plants and fruits will benefit more from blue light than red light, simply because they're not used to receiving a lot of red light in their natural environment.

However, if your hydroponic grow light system includes both red and blue color temperatures, you don't risk not giving your plants the light they need.

Even if a plant won't make much use of, say, red light color temperatures, they won't do it any harm either.

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