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Purple light for plants: secondary source and enhancer

Plants use the different colors emitted by the light spectrum to feed during their growth and development cycles. In the case of purple light for plants, we know that it is effective for the growth and development of any plant, but only as a secondary light source. Specifically, purple light encourages the lush vegetation of a plant to be achieved and both its flavor and aroma to be enhanced.

In addition, purple light also generates other positive aspects about plants that we will tell you next, along with an explanation regarding the origin of this color of light, its effectiveness on plants in general and the types of artificial lights that provide it; especially for indoor crops.

Purple light for plants growth

Although purple light for plants acts in a secondary role, it is a complementary element that is important for plants to develop by being more leafy. It is for that reason that they are within the spectrum of light offered by grow lights.

In fact, it is LED lights that can currently provide the greatest benefits to indoor cultivation. This is because it has been years of studies of the visible light spectrum - and experiments with growing plants - that allowed us to take as a result, that these types of lights are the ones that provide a much healthier growth to the plants and that it resembles in great proportion to the light that the sun can give.

In contrast, HPS or MH lights, which emit glows of white and orange light, are not as beneficial to plants (at least not on their own). Although it is believed that with white light (as it is believed to be that of the sun) the plant will be fed with a full light spectrum of energy, it is not so. Even the colors they emit are less necessary for plants, than are the blue color and the red color.

But where is the purple light for plants at this point?

The purple glow that many LED lights emit is the product of the union of blue and red diodes (mostly); which are the most efficient colors for both growth and flowering and fruiting of plants.

In addition, LED lights are composed of different wavelengths of light, which include green, yellow, orange and white diodes - but in smaller quantities - because they also add to the growth of plants when they act together.


In some cases, a purple light is observed for plants that may be lighter (violet), darker (magenta) or with a tendency towards pink. This happens because, after the combinations of the different wavelengths, the emission of some diodes (colors of lights) is intensified more than others, with the intention of adjusting the amount of light sufficient for a plant in a certain period or stage of its growth.

This reason explains the fact that, when building an LED light, manufacturers decide how many colors to place inside it, so that the light emission is then adjusted to what they want to achieve with the plants.

For example, knowing that blue light promotes plant growth, more of it will be placed when you want the plant to grow a little more compactly. But if you want the development of this to be elongated, you will place more colors far red, orange, green and yellow, with a predominance of blue and red.

And if you want to enhance the taste, smell and health of the plant, it will then be stimulated through a purple light.

However, in other words, it is important to remind you that when using LED grow lights, the most important thing for plants is to stimulate all their growth patterns at the same time; therefore, we recommend you to find lights that have the full spectrum of colors.

What does purple light do for plants?

Purple light for plants is responsible for enhancing the smell, taste and healthy growth of your plant. Therefore, it also works as the best transmitter of blue and red wavelengths, making them have what they need to grow, without falling into excesses.

We have said that the mixture of blue and red colors promotes a purple light towards plants. And also, whether it contains more red light or more blue light, the growth effect will be positive towards one edge or another (because we already know what each color works for).

But, if you want to achieve specific results for your crop, you should know that the shades of purple light you provide to your plants may vary depending on your purposes. For example:

  • If you want your buds to be stronger and the plant to have more leaves, you will need a redder than blue color to be emitted and that will result in a magenta hue in your light.
  • If you want your plants to grow taller or bushier, you'll need to use a little more blue light and if you do, your lights will look in a darker or deeper purple hue.
  • And if you want the plants to have all the colors so that a balanced growth is enhanced, you will need to provide it with a light purple/pink tone and that will be achieved, adding diodes of lighter colors such as white.


Is purple light good for plants?

Yes. Purple light for plants is known to enhance various elements in their growth and photosynthetic activity, because it results from the combination of blue and red color diodes. However, by emitting only purple light to your plants, you will not achieve the most optimal result; because, as we have said, the more wavelengths of light are emitted to your plant, the more balanced its growth will be.

In that sense, the companies that produce LED lights, noticing that the color red and blue are the ones that work best for indoor crops, decided to create purple lights for plants, which would obtain the amount of red and blue suitable and necessary for the growth of plants in crops to be enhanced.

As a positive aspect, quality LED lights are obtained that provide a lot of energy savings, they are built and sold at affordable costs (because red and blue diodes are economical), as well as very beneficial for crops.

In short, providing purple light for growing plants is a very beneficial bet, thanks to the fact that it reaches the maximum growth potential of a plant and a complete crop.

Growth stages in which purple light for plants is most effective

Taking into account that red light is responsible for stimulating seed germination, root growth, promoting the conversion of nutrients into energy and stimulating both flowering and fruiting, we can notice that in some plant growth cycles, more red light will be needed than blue; which promotes the absorption of nutrients through photosynthesis and therefore the growth of plants.

In that sense, depending on the stage, we already know that a certain proportion of red and blue light must be handled in the purple lights. And adding to the above, that will also depend on the way you want them to grow; if it is a small environment and requires controlling the growth of plants, then emit more blue light and at the time of flowering, exchange for more red light.

Purple light for plants is most beneficial when it is in its seed germination stage; then, when it develops its vegetative cycle (while it is producing its stems and leaves) and finally, when it reaches the stage of flowering and fruiting.

Efficiency of purple light in Cannabis plants

The cultivation of cannabis indoors has become more in demand, thanks to recent struggles for the legalization of its use for medicinal and recreational purposes.

That is why there are several very recent investigations that have studied the spectrum of visible light and its specific functioning on cannabis plants; precisely with the intention of creating the perfect LED lights to enhance your growth, taste, smell and above all your health; because whether these are for personal consumption or for sale, the healthier the plants, the better results they will provide at the time of consumption.

Therefore, it has been obtained that the spectrum of light that can be more positive for cannabis plants is the purple color and that this can be found in the various brands of LED lights.


In addition to this, we know that there are many companies that have managed to create lights with customization options for light emission, focused on transmitting certain colors to plants, at a certain stage of their growth, to make the process much more efficient and take advantage of the incidence of artificial lights on them.

Above all, because although legalization has been allowed in many places, there are different restrictions regarding its cultivation and consumption; such as the fact that it must be out of sight of all people, that is, be cultivated in preferably private and closed places.

As a result, the need to make the plants grow, but rather than lengthen, they are rather bushy comes into force; In that sense, the manipulation of the amount of blue and red light they receive is perfect to control this growth factor through the use of purple light for plants.

Tips to make better use of purple light for Cannabis plants

If a grower wants to obtain higher quality cannabis plants, in addition to controlling the temperature of the space, humidity and the entire environment of their crop, they must control the intensity of light and the variations of the color spectrum that they will need.

Achieving this is only possible thanks to advanced LED grow lights. Here are some tips on how to get the most out of them according to the growth stage of your cannabis plant:

  • At the stage of germination of the seed, what is wanted is that the structure of the roots is as strong as possible. Therefore, higher proportions of red and far red light are recommended.
  • The proportion of red light should be higher, if you have a crop full of plants and you want them to grow more long than thick. But, if you want to control that growth at an optimal height, it is complemented by distant red light.
  • LED lights for cultivation have the possibility of programming the spectrum of light that they will emit at certain times. Therefore, it is recommended to take advantage of this tool to build a light emission plan for the plants that is for the number of hours they require.
  • When the plant exceeds its vegetative growth and enters the flowering stage, it will be necessary to emit a spectrum of light mixed with all wavelengths.


Finally, we remind you that purple light for cannabis plants is a resource that you can not stop counting on within your growing, because the positive aspects and benefits that will provide both your plants and their final production, will be those that we have mentioned and many more.

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