What Happens if Cannabis Plants Gets Too Much Light?

Your greenhouse depends on several factors to ensure plants are able to grow efficiently. One of these factors would include lighting.

Without appropriate lighting and exposure in the greenhouse, you may find that your plants are not flourishing as they should. 

Plants depend on light in order for photosynthesis to occur. This is essentially a process of energy transference and ensures plants are able to continue growing.

When adding light exposure to the greenhouse, a few things need to be considered. So the question is, can indoor plants and cannabis gets too much light?

With that said, too much light could cause damage to your plants, whereas insufficient light could halt the growth process. 

In this post, we investigate the role of light and sun exposure in the growth process of plants.

We also consider how much light plants should get, and whether it is possible for a plant to be exposed to too much light.

The post will also share a few useful tips to help you optimize the lighting in your greenhouse more effectively. 

cannabis get too much light
Young leaf of marijuana plant detail at sunset. Selective focus. Low depth of field.

Light Exposure In Your Greenhouse or Grow Tent

If you have your own greenhouse, then you are already familiar with the term “photosynthesis”. This is a critical part of a green plant’s survival process.

These plants rely on light in order to perform the photosynthesis process. While you may be familiar with the term, many people do not thoroughly understand how the process works. 

To get an idea of why light is important in a greenhouse, it is important to know how green plants use light. It is also important to have a good understanding of how light is involved in photosynthesis. 

There are a few steps involved in the photosynthesis process. Let’s start by looking at these steps:

  • The plant absorbs both H20 and CO2. This absorption process occurs when these elements come into contact with the leaves of the plant. 
  • Thylakoids form part of the plant leaves. As light reflects on the leaves, the rays hit pigments that are found in the leaf membrane. Once this happens, electrons and enzymes start to perform actions to absorb the light. 
  • Conversion processes are performed, which then causes a “calvin cycle” to initiate. ADP in the plant is converted to a usable form, known as ATP. The enzymes also cause a conversion between NADP+ and NADPH. 
  • The converted compounds are used in this calvin cycle process. The process helps to convert carbon dioxide, which is also absorbed by the plant, into a type of glucose. The glucose is then used to fuel cells in the plant. 

As you can see with the description of photosynthesis, light plays an important part of a plant’s lifecycle.

It allows the plant to create a source of energy – which is required by the plant to continue growing. In the absence of light, this process would not occur – potentially leading to a dying plant instead of one that continues to thrive. 

The role of light differs between different plant types. Some plants have a greater need for light exposure, while others may rather prefer darker environments.

This is why it is always important to consider the plants you will be using when designing the layout of your greenhouse.

It is also useful to consider the types of plants inside the greenhouse when you turn to artificial lights used to stimulate enhanced growth. 

What Damage Occurs When Cannabis Gets Too Much Light?

One of the most important factors in a greenhouse lies in understanding how much light plants need. As we have explained, not all plants have the same need in terms of lighting.

Some plants will require more frequent and consistent exposure. 

In addition to understanding the photosynthesis process and related factors, you should understand what too much light can do.

Many greenhouse owners think about fitting the environment with UV lights. This can greatly enhance the stimulation of plant growth.

At the same time, there is a concern that too much light could be bad for the plants. 

When considering the potential effects of too much light exposure, it is important to consider the type of lighting solution that is used.

Different light sources can be used to ensure plants are able to generate energy. The effects of these lighting sources tend to differ. 

Natural Sunlight 

The most natural form of lighting would be UV rays from the sun. This is also one of the most common resources to use when adding light to your greenhouse.

When relying on sunlight as a means of activating photosynthesis, then you will usually build your greenhouse with windows at the top.

The windows would allow the UV rays to penetrate into your greenhouse. In turn, plants gain access to a direct source of UV rays, allowing for photosynthesis to occur. 

Indoor plants Get Too Much Light

Sunlight, however, also comes with a few disadvantages:

  • The sun is only out during certain times of the day. When relying on sunlight, your plants would only be exposed to these UV rays at the specific times the sun is out. 
  • During the year, sunrise and sunset times tend to alter a bit. This can create problems with the schedules you use to ensure plants gain adequate access to the UV rays. 
  • When the weather is not playing along, which can include a cloudy sky, UV exposure may be limited inside the greenhouse. 

In addition to these effects, consider the fact that on warm days, the sun can cause excessive heat accumulation inside the greenhouse.

At the same time, the sun’s UV rays may also lead to excessive heating of plant leaves. 

Long-term exposure to such heat may cause the plant to suffer damage. This could create a browning at the edges of the leaves, for example.

Plant leaves could also start to lose some of their color, as the excessive heat and UV exposure could have a “bleaching” effect on the leaves. 

Artificial UV Lights

Sunlight is not the only source of UV rays that can be used to stimulate a photosynthesis process in plants.

When you have a greenhouse, it is possible to set up UV lights in the structure too. UV lights can be a great option when you need to schedule light exposure.

This can also be an effective option when you need to provide 24/7 light exposure to plants, or for plants that only need to be exposed to light for a short period each day. 

UV lights can be customized to fit any structure within your greenhouse. You can choose to mount these lights on the roof, which will provide UV exposure to the entire environment.

In other cases, you may choose smaller UV lights that are fitted in boxes. This allows you to have extra control over specific areas – ensuring each plant can have its own exposure schedule. 

You can even get a light controller to ensure that your plants are being exposed to the optimal amount of UV light.

With artificial UV lights, there can be consistent exposure without some of the risks that come with sunlight. In particular, UV lights will not cause as much of a heat build-up compared to sunlight.

In fact, with a few strategies, you can effectively manage the temperature of the greenhouse when using artificial UV lights. 

A UV light is also a great option for indoor plants. When you have indoor plants, you may find that it is harder to effectively regulate light exposure.

There are a couple of options that can be used for indoor plants. 

The Elaine LED Grow Light is just one example. This light is fitted with 60W LED globes that are able to turn on and off automatically.

The system comes with three timer settings, including a three-hour, six-hour, and a 12-hour option. There are five brightness levels to choose from too.

The customization options give you the control that you need to promote growth – which is beneficial when compared to sunlight, as you have no control over natural UV exposure and temperature. 

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How Much Light Is Too Much?

Measuring light is difficult, but there are some techniques that can be used to determine how much lighting is needed for plants.

When it comes to determining the amount of light needed, there are a couple of factors that need to be taken into account. 

The first thing to consider is the type of plants that you are growing. If you are not too familiar with the plants, some research into the species would be highly recommended.

Try to learn more about the light requirements of this plant type. 

There are some plants that require consistent exposure to light. In this scenario, there may not be a point where light could be considered “too much”.

This is also the scenario where you want to use equipment that can help to provide UV light to plants when the sun is not out. 

For other types of plants, specific scheduling of light exposure may be necessary. In such a scenario, you can position the plants to benefit from natural sunlight.

You can also use a plant growth light with a timer to set the schedules. 

A good example is the Ankace Grow Light. LED lights with a 60W power rating is used, along with a tri-head design. The light system gives you three different timer options that can be used to customize light provisioning to your plants. 

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Optimizing Light Exposure In Your Greenhouse or Grow Tent

Light exposure in a greenhouse should be configured to ensure all plants inside can benefit. Plants that require more exposure to light should be placed in open areas.

Those plants that only require a little light exposure each day should be more isolated. Exposing these to excessive light could prove problematic when you are trying to create healthy plants. 

Cannabis in grow tent
legal marijuana concept. Medical cannabis flag background

With the factors we looked at in mind, you should ensure you understand how lighting can be optimized for your greenhouse.

A number of strategies can be used. The specific techniques that you can use to optimize lighting depend on the layout of your greenhouse, the size, and the types of plants that you are using. 

You should also consider whether you have indoor plants in a small greenhouse, or have a large greenhouse outside with a more significant variety of plants.

Optimizing lighting for these structures will be different. 

Optimizing Lighting For Indoor Greenhouses or Grow Tents

In cases where you are growing plants indoors, you may have a small greenhouse that only provides space for a couple of plants.

This is a great way to grow your plants while also adding décor to your house. Direct sunlight exposure to the plants at an early growth stage may not be the best solution, as this may lead to too much heat. 

There is a number of grow lights that can be used instead. These grow lights are easy to use and do not take up too much space. You will simply place the light on the same desk or shelf as the plants. 

The Soberto Grow Light is one of the most effective options for indoor plants. You can place this light directly over indoor plants, or position it next to a portable greenhouse.

With four lights included in a single system, you get better exposure.

A wireless remote control allows you to easily adjust the settings of the lighting system without having to physically interact with it.

The upper wires are flexible, allowing you to modify their positions with ease. 

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If you have a larger area where you are adding plants indoors, then you might want to consider a system that provides enhanced exposure.

The Roleadro LED Grow Light Strip is a good option. The system is easy to use and comes with four dimmable light settings. The light string can be attached to any structure close to your plants.

The system comes with a built-in auto on and off function, a timer, and even includes an extension cable. 

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Optimizing Lighting For Outdoor Greenhouses or Grow Tent

With an outdoor greenhouse, you will usually find yourself in need of lights that cover bigger areas. Start by considering the structure of the greenhouse.

How much light do you need?

Also, consider whether all plants require the same lighting schedule. If there are different needs, you may need to think about buying multiple lighting setups.

The Honesorn 600W LED Grow Light is a good example of a highly effective system that won’t break the bank.

The 600W power rating of the LED lamps provides better heating and light exposure for your plants. You can switch between Infrared and UV lighting.

The full spectrum lighting design ensures your plants are able to experience benefits similar to that of natural sunlight. 

Honesorn 600W LED Grow Light, Full Spectrum Growing Lamp with Veg&Bloom Switch UV&IR, Indoor Garden Plant Light with Adjustable Rope, Grow Lights for Indoor Plants, Greenhouse (600w)

A built-in cooling system in the light ensures there is no risk of overheating, even with a high 600W power rating.

Heat effectively dissipates without causing problems with your plants – such as bleaching or burning the edges of leaves. 

Larger lighting systems are also available, but will take away some of the individual control you have for each type of plant in your outdoor greenhouse. 


Plant growth largely depends on a photosynthesis process. This process occurs when the plant is exposed to light.

The light is absorbed and then processed in the plant, and essentially turned into a usable energy source. 

Too much light can be bad for some plants but maybe beneficial for other plants.

Direct sunlight, however, can cause plants to heat up too significantly. This can lead to adverse effects, including burnt edges and bleaching.

Learn how much light each plant needs, then consider using an optimization technique to improve photosynthesis, while also reducing risks. 

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