Everything you need to know about UV grow lights.
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All you need to know about UV grow lights

There has been some argument over just how important UV light is for the plant growing process. Some growers are even skeptical whether ultraviolet light even needs to be used in the cultivation of plants at all. However, if you are growing plants inside, then it is absolutely the case that you should be giving your plants exposure to UV light on a regular basis.

In fact, UV grows lights are the most important piece of equipment in your grow room. When you have the right UV light, it is always going to be easier to produce higher quality cannabis at higher levels, which means you can sell it for a higher profit. This is basic common sense really - plants thrive when they have adequate access to sunlight, and although UV lights are not sunlight, they can do a pretty good job of mimicking it.

With that in mind, let’s take a deep dive into UV grow lights, what they are, what they do, and why they are so important to your setup

What is UV Light ?

First of all, let’s take a closer look at exactly what UV light is because the more you understand about UV light and how it works, the easier it will be for you to incorporate it into your grow rooms and harness its unparalleled power for growing plants.

Basically, in layman’s terms, ultraviolet light, or UV as it is often shortened to, is actually a form of electromagnetic radiation which is cumulated in natural sunlight. Whenever you stop outside in the sunlight, you will be exposed to UV light, which is why you need to wear sunscreen.

Plantation of plant grow with natural UV light

UV light has three main wavelengths

  •  UVA
  •  UVB
  •  UVC

As you will probably know, plants need sunlight to grow and thrive effectively. However, it is only UVA and UVB, not UVC which are useful to plants, and which can help them to thrive and flower in great abundance. In fact, UVCX is filtered out by the ozone layer, which means plants in their natural outdoor environment are never subjected to it.

Some of you reading this might be aware that there is technically a fourth form of UV light, which has a wavelength of between 10 nm and 180 nm. This form of UV light is known as Vacuum or extreme UV because it can only be found in a vacuum, which means it is not important to us as growers - we only really need to know about UVA and UVB, so let’s take a closer look at them…

UVA: Ultraviolet A is a form of light that has wavelengths of 320-400 nm. Around 3 percent of UVA light is made up of photons that cannot be detected in natural sunlight when it enters the earth’s atmosphere. This form of ultraviolet life is not dangerous to humans or animals.

UVB: Ultraviolet B is a form of light characterized by wavelengths of 29-320 nm. Approximately one firth of natural sunlight is contained in UVB. Ultraviolet B is also the more problematic form of UV light that can cause cancers and skin damage in humans and animals. However, it is much easier for the ozone layer to clock it out due to its unique composition, which means it rarely does too much damage.

What are the pros and cons of UV grow lights?

Now that you know a bit more about what UV light is, let’s take a look at how it influences plants, and what the benefits of using a UV grow light may be.

Before we go any further, it’s worth noting that different plants react differently to UV light depending on what kind of UV light it is and what species of plant you are talking about. That being said, below are some of the pros and cons of using UV grow lights for you to consider: 

Pros of UV grow lights for growing

Improved flavor and potency: Some studies have shown that UVB and UVA exposure is able to increase the production of terpenes and flavonoids in plants. For example, tomatoes grown without UV lights were shown to be less aromatic or flavorful than those that were put under UV grow lights. In fact, one study found that flowers that were grown without UV light had as much as 6 fewer vital terpenes than those that were grown using UV grow lights. That means that by using UV grow lights you can improve the smell and taste of your flower significantly.

Not only that, but some studies have shown that UV grow lights are able to increase the amount of oils and resins contained in plants grown with that in mind, which means you can grow more potent plants, which are of course more valuable if you use a UV grow light.

Improved resistance to disease: Another key benefit of using UV grow lights is the fact that UV exposure could help your plants to be more resistant to both disease and stress.

Plants are able to produce as many as 15 different defense proteins from the second they re-exposed to UV light, which is a bit like us humans developing our immune systems when we are exposed to the right mix of essential nutrients. It helps the plants to fight back against insects, fungus, and bacteria that could otherwise kill them off.

Not only that but UV light is able to kill numerous microorganisms that could pose a threat to your plants. Wavelengths that are shorter than approximately 300 nm are the most effective for this purpose.

Speedier germination process: Another big benefit of using UV grow lights is the fact that UV light can encourage faster germination of seeds. Not only that, but UV light can also cut the “shock” time of seeds and get them ready for higher intensities of light, all of which will help your seed to thrive.

Cons of UV grow lights for growing

It can be expensive: Although there are many benefits to using UV grow lights, it is important that you are aware of the cons too. The main downside of using UV grow lights is that it can be expensive, especially if you have to have them turned on all the time. However, you should bear in mind that with an increased electricity bill comes an increased yield of higher quality, which could offset the cost of running UV grow lights and then some!

You may need several sets: As we mentioned earlier, different plants thrive better when exposed to different types of UV light, and some will indeed a combination of lights to grow as efficiently as possible, which means you may need to invest in several different kinds of bulbs.

As you can see, although there are pros and cons that come with using UV grow lights for your plants, the pros definitely outweigh the cons in terms of providing you with a higher, more valuable crop, which means you should probably think about adding UV lights to your grow room as soon as possible if you haven’t already.

When do plants require UV light?

Some people argue that you should not use UV grow lights until you are trying to make your plants flower. This is because UV lights can be expensive, and they reason that it’s a waste of money to use them at the vegetative stage of growth.

However, if you want to produce the best flower, you should absolutely invest in growing the best veg because the better quality the veg, the more likely you are to produce a high-quality flower too.

That is why we would definitely recommend using UV grow lights for a full cycle - from germinating the dees to harvesting the flower. If you do this, you will give your plants the best possible chance of growing and thriving. Your plants will probably be healthier, happier, and more potent if you can do this, and you will be able to harvest a far higher yield too.

How much UV light is needed?

A lot less UV light is needed than you might think. In fact, for most plants, UV grow lights that give off as little as 2 or 3 watts of light per square foot is more than adequate. So, for example, if you have a grow tent of 8’x8’, you would need just 64-96 watts for the whole operation. UV lights and the growing stages, Plants like cannabis have two distinct growth stages. These are

The vegetative stage

This is when the plants are starting their life eas seedlings or clone leads right up until vegetative matter starts to grow leaves and stems. 

When your plants are in the vegetative stage, you should provide them with 18 to 24 hours of UV light each day to give the seedlings the best chance of germinating and growing into healthy high-yielding plants.

The flowering stage

This is when the buds start to grow right up until such time as you harvest them.

During this stage, your plants will require 12 hours of darkness each day and this should be uninterrupted by light, but for the remaining 12 hours, you should turn your bulbs on at a low setting to maximize the crop and improve potency.

It’s a really good idea when growing indoors to try, as much as possible, to mimic the light cycle the plants would be experiencing if they were growing outdoors as, of course, this is the most natural state of rhythm to be in, and thus the most conducive to growing a decent crop.

Flowering stage of plant

Can UV light be harmful to plants?

One question we are asked a lot is whether UV lights can be harmful to plants. Although it is possible for UV lights to cause harm to your plants if, say you leave them on for too long or use too powerful a bulb, for the most part, UV grow lights are completely safe for your plants, which is why you should always make sure you buy UV lights that have been designed for the specific purpose you are using them for, and that you follow all of the instructions provided.

Can UV lights harm people?

Again, for the most part, UV lights are completely safe to use when you use them correctly. However, if you expose yourself to them without wearing sunscreen or taking other precautions, they can be dangerous to your skin, even more so than the sun because you are always going to be closer to your UV grow lights than the sun!

In order to keep yourself safe, put on sunscreen, wear long sleeves and protective eyewear whenever you are going to be near your UV lights and you should be absolutely fine.

Is there a best UV light for growing plants?

There are lots of UV grow lights on the market, so it can be difficult to find the best ones for your plants, but if you take the time to choose the highest quality lights you can afford, you will be off to a great start.

Ideally, you should also look for lights that provide a full spectrum of UV because these will mimic natural sunlight more effectively than many other lights, which is exactly what you need them to do. After all, plants naturally grow outdoors and that is what they are accustomed to, so lights that can give you that effect indoors will always make your plants happier than lights that operate on a lesser spectrum.

If you want to find out more about UV grow lights, or you want to buy high-quality lights that will help you improve your yield in terms of volume and potency, do not hesitate to get in touch with our team of experts here at GROWEALTH today. We know all there is to know about harnessing the power of UV light to grow better plants and we are willing to share that information with you so that you too can up your growing game, produce better quality plants, and make more money than ever before. Hit us up!

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