Is Too Much Light on Plants a Bad Thing? [ANSWERED]

Believe it or not, there is such a thing as too much light on plants.

Like us, plants need periods of darkness in their day to rest and remain strong. Plants that have been exposed to too much light will show symptoms, like:

  • initial loss of color or pale leaves,
  • yellowing leaves at the top of the plant, with
  • browning at the tips (like sunburn),
too much light on plants

Today, at the Garden Bench Top, we are going to tackle all those questions about too much light on plants. We’ll look at what happens to a plant that is on the receiving end of too much light. We’ll also gain a better understanding of different types of lighting, and how you can adjust your lighting for your own plants.

So, if you’re ready grab a pair of sunglasses, because it’s about to get bright in here!

What Happens if a Plant has Too Much Light?

Plants that are over-exposed to light will exhibit some tell-tale symptoms – or cries for help – to tell you that some immediate action is required.

too much light on plants
credit: giphy

Failure to recognize these signs of too much light, will often result in a quick decline in your plants’ health, eventually leading to death.

As we mentioned earlier, a plant requires darkness to rest and recuperate from the days’ growth. It would be like keeping you in a room with constant light for 7 days straight. The constant light will lead to sleep deprivation, which will eventually lead to a significant reduction in your mental and physical capabilities.

In addition, depending on the light source, the constant heat from the light can dry your plant out to the point of complete dehydration. And we don’t think we need to tell you what happens after that.

So what are these ‘tell-tale’ symptoms that you should be looking for in your plants? We will explore these signs in the next section.

How to tell if a plant is getting too much light?

We’ve already touched on a few of the symptoms that plants show when exposed to too much light, such as changes in conditions for your plants leaves. In this section, we’ll explore those changes in more detail.

When a plant is stressed, the first places where symptoms are shown are generally in the leaves.

Leaves are one of a plants’ most vulnerable parts, but also one of their most vital organs. So, when leaves start to fail or change, it is time to jump into action.

Plants that receive too much light experience leaf burn.

Leaf Burn from too much light on plant

You can easily distinguish if your plant is experiencing leaf burn, compared to other changes in leaf conditions caused by other diseases, like yellow leaves or brown leaves.

Leaf burn first shows at the top of your plants, with yellow leaves coupled with veins that remain green. You may also observe some leaves that have begun to brown and appear sunburned, as your plant remains exposed to light.

If your plant has been exposed to too much light for an extended period of time, you will see its health declining with drooping leaves, and an overall sad appearance.

How Much Light is Too Much Light for Plants?

The length of darkness will vary from species to species. And some species will even differ by region. However, a general rule of thumb for plant light exposure is to base their cycle on a similar one to ours.

too much light on plants
Photographer: Michanne Lisa | Credit: Unsplash

Anywhere between 12-14 hours of natural daylight will be optimal for their growing needs, as well as provide them with ample time for some dark downtime.

If you have indoor plants, under artificial light (not direct light through a window from the sun), you can extend the lighting period up to 16 hours (18 hours if it is a very low intensity light). However, 24-hour light will result in your plant being over-exposed, with leaf burn on your plants.

The biggest worry would be indoor plants in offices that have lights on for extended periods of time. In these cases, we would suggest implementing a rotation program for your plants. Every month, swap out the over-exposed plants in your office for plants that have had periods of rest (and ideally, exposure to direct excess sunlight during the day).

Understanding Different Types of lighting

As we just touched upon in the previous section, there are different types of light that a plant can be exposed to. And as we demonstrated, different types of light will change the duration a plant can tolerate before it is considered over exposed.

Light intensity

Light comes in different forms and intensities.

For example, if you have been a plant parent to indoor plants for a while, you will understand some houseplants require direct natural sunlight, whereas others prefer indirect sunlight only. The difference between the two forms of light is the intensity.

too much light on plants
Photographer: Yen Vu | Source: Unsplash

Direct light means the plant is in full direct sunlight, which is accompanied by heat. Unless the plant has natural forms of protection against heat, like succulents, your plant can quickly dehydrate. And let us tell you, a dehydrated plant is not a path you want to go down. It often leads to weakened plants, that are susceptible to diseases and pests.

At the very least, a lack of moisture results in your plants’ leaves turning yellow and brown, droopy and in some extreme cases, falling off the main plant.

Light duration

The other aspect of lighting that needs to be considered is duration.

We are assuming this is something you have already contemplated, given you are searching for the answer to can you have too much light on plants?

In terms of duration, a plant can not have too much natural light. If plants could not survive periods of natural light, we wouldn’t have forests and woodlands. Whatever the sun throws at plants in the wild, they will thrive in or develop adaptations to allow them to live in nature.

However, for artificial (indoor) light, a plant can most definitely have too much light. This is because, artificial light (as it sounds), is man-made and not natural. There is nothing natural for a plant to be exposed to light all day and all night long.

As we said earlier, plants need down-time. They need to break from the growing processes that occur when they are exposed to light. And they can only rest while it is dark.

Frequently Asked Questions

In this section we attempt to answer all your ‘other’ questions that may not be addressed in our article too much light on plants.

Keep in mind, if you don’t find an answer to your question, please send us a message via our CONTACT page. We will endeavor to respond with a timely answer, and include it in our growing FAQ section below.

Can a plant recover from too much light?

We would like to say, YES, plants can recover from sun damage and over-exposure to light. However, we want to preface that by saying it depends on how early you catch the problem.

Your plant has a better chance of being revived if you catch the problem early. If your plant has been deprived of water and completely dehydrated, the damage may be too extensive, and your plant will continue to perish.

Can Plants Get too Much LED Light?

Even though LED lighting is not as intense or releases as much heat as other forms of lighting (such as candescent lighting), plants can still suffer from light over-exposure.

It doesn’t matter what type of light a plant is exposed to, if it is exposed for periods greater than 16 hours (12 hours direct sun light), with minimum darkened periods in between, then it is likely to suffer from leaf burn.

Can LED Lights Burn Plants?

Yes LED lights can burn the leaves of the plants. High intensity LED lights can be too much for plants, especially when they are extremely close to the plants. Exposing plants for long periods to lights (as we have discussed) will also lead to leaf burn.

How do you revive a plant that gets too much sun?

Immediately water your plant to ensure it does not get dehydrated. Make sure any excess water drains from the area/container that you plant is in. Your plant will already be weakened by the sun, it will not be able to fight off any bacterial attacks or other forms of disease like root rot.

If your plant can be moved, we recommend finding a shaded spot for your plant to recover from its sun burn.