Do Plants Grow At Night or Do Plants Sleep? All Your Curiosities Answered!

Ever wonder what happens in the plant world once the sun goes down? Do plants grow at night or do plants sleep? We often don’t give a moment’s thought to what a plant does at night. The old adage “Out of sight, out of mind” rings true. Well, it’s about time we did a bit of digging into the wonders of your garden after dark.

Yes – plants do grow at night. In fact, would it surprise you if we said there is a hive of activity in your garden at night? And we’re not talking about animals or pests doing night raids on your vegetable patch! A lot happens to your plants at night at a cellular level. It is called respiration, which is a fundamental part of your plants’ growing process. In short, respiration is when your plants process the glucose produced during the day via photosynthesis. We’ll get into the details more in the following sections so stay tuned.

Do Plants Grow at Night

Welcome to today’s feature article at the Garden Bench Top – where we are putting on our night vision goggles and exploring the world of plants at night. In this article you can expect to learn about the inner workings of your plants at night. What happens, the processes and reasons why plants grow at night.

So if you’re ready, grab a torch because it’s about to get dark here.

What Do Plants Do at Night?

Believe it or not, plants are as active during the night, as they are during the daylight hours.

And the two periods (day and night) can be broken down into two processes: photosynthesis and respiration.

Photosynthesis is an important element of our life, because without plants producing oxygen, we would cease to exist. As such, most people are familiar with, and associate plants with photosynthesis. It is the process where plants use sunlight, carbon dioxide, and water to convert glucose and oxygen. Given photosynthesis requires sunlight, this process must happen during the daytime, where plants will absorb as much sunlight as they can.

But what people are less familiar with is the respiration part of the cycle, which occurs at nighttime. Respiration is when the plant uses glucose (produced during photosynthesis) and oxygen to produce energy for growth, as well as carbon dioxide and water.

We know we’ve just thrown a lot of scientific terms around, so here is a diagram to visually explain the process.

Photosynthesis and cellular respiration comparison vector illustration. Biological process explanation in day and night. Oxygen, carbon dioxide, sugars, minerals and water system explanation scheme.
Photosynthesis and cellular respiration comparison vector illustration. Biological process explanation in day and night. Oxygen, carbon dioxide, sugars, minerals and water system explanation scheme.

As you can see from the above diagram, both oxygen and carbon dioxide is used and released during the cycle.

So how come we believe plants provide the oxygen that we require so desperately to live? It is because plants have a net positive effect on their oxygen consumption and release. In other words, they release more oxygen than they consume. And the same goes for carbon dioxide, only in reverse.

Do Plants Grow at Night?

do plants grow in the dark

So, bringing this discussion back around to the initial question – do plants grow at night? What does the photosynthesis / respiration cycle have to do with growth?

These processes release energy that the plant can then use for growth and fundamental functions. While the plant uses energy to spread its leaves out during the daytime to absorb sunlight, it focuses the nighttime energy on plant growth and cellular repair.

In fact, a research paper released in 2008 by the SALK institute for Biological Studies found that the prime time for plants to grow was just before dawn. This is when plants concentrate their energy to grow as a survival mechanism.

Yes – you read correctly. As you learned earlier, plants rely on the sun for photosynthesis and their survival. Therefore, they need to grow towards and increase their exposure to the sun. And it is this period before dawn, where they concentrate their energy on pushing and growing towards their closest light source.

Check out this time-lapse of watercress growing towards the light in a dark room. Not only is it mesmerizing to watch, but it also shows how plants grow at night to reach for the light.

You may even have seen this process in play in your very own yard. Have you ever noticed a stray plant (or weed) that sprouted in an out-of-the-way position that received very little sun?

As the plant continues to grow, it realizes there is a lack of light, and it stretches and grows in awkward positions in search of light. This unusual growing pattern is purely for survival. If it doesn’t receive enough sunlight, it will not be able to produce enough energy to grow, and ultimately die of starvation.

Do Plants Sleep? How Much Darkness Do Plants Need?

Do Plants Sleep?

Yes, you could say that plants do sleep, although not in the traditional sense that humans do.

Plants still have active plant cells, and they require a period of complete darkness to perform their respiratory processes.

Seedlings require a minimum of around 6-8 hours of darkness, while mature plants require longer periods of around 8-10 hours of no light.

In fact, we have discussed how much light is too much light in another feature article. In the article, too much artificial light resulted in the plants suffering from light-stress. It also caused dehydration, and the leaves to suffer leaf burn and become crispy from the constant and unrelenting heat.

Can Too Much Artificial Light Harm Plants?

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 sunlight), with minimum darkened periods in between, then it is likely to suffer from leaf burn.

If you have indoor plants that are exposed to constant lighting conditions (like office plants), we recommend putting them in a rotation. Simply swap the plants out every month, to allow them to recoup and recover from the unrelenting light. If that isn’t convenient, try covering them for periods during the night with block out material.

Final Thoughts on Do Plants Grow at Night

Nighttime is an important period for plants to perform their respiration processes, and complete the energy producing cycle.

They remain active during the night, and often focus their energy on growing and producing new leaves. In fact, when they are not receiving enough sunlight during the day, they will concentrate on growing in the period just before dawn. This gives them the best chance of reaching light, and ensuring their survival.

Given all this occurs while we are asleep, it is hard to observe. However, if you perform your own time-lapse experiment on your plants, you’ll soon see how much growth occurs under the cover of darkness.