How many hours of daylight do plants need?


The sun is the main source of energy for almost every living thing on earth. Sunlight especially is essential for plants since it’s only plants that use sunlight to produce oxygen which is the air that humans and most animals breathe.

A plant may need at least six hours of direct sunshine, where most of them survive with roughly three to six hours of direct sunshine every day. At the same time, the plants need protection from the intense sun, so don’t leave them directly out in the sun for too long.

It also helps to search for your specific plant’s sunlight needs because they differ from plant to plant.

How does a plant use daylight?

Plants entirely depend on the energy from the sun to reproduce. There are key processes like photosynthesis that take place in plants when they get direct sunshine.

Photosynthesis is the process whereby green plants transform light energy into chemical energy.

In this photosynthesis process, the plants’ energy produces by-products such as oxygen and sugars in plants. According to research, the carbon dioxide in the air combines with the plants’ water to produce sugars and oxygen in a series of reactions.

Plants need a specified amount of sunlight, so sometimes, when the plants absorb a lot of sunlight than needed, the excess energy may cause critical damage to the plant’s proteins.

What do plants do with the excess daylight that they receive?

For the plants to protect themselves from the excess energy, they convert it to heat and send it back out to the environment. Depending on the amount of energy absorbed, the plants can reject 70 percent of the sunlight’s energy.

In cases of deficiency of sunlight, the plants store energy in the form of starch. They are complex carbohydrates that can be broken down to glucose for the plants to use for energy.

Why do plants need daylight?

All living things need the energy to grow. We get energy from the food that we consume. Plants get their energy from light through photosynthesis without light the plants will be unable to produce the energy that it needs to grow.

This process will be further explained in the next part as well as its stages.

Process of photosynthesis

Photosynthesis is a complex process with two main stages.

The first stage is the light-independent stage, where when the sunray hits the surface of the leaf. Then the light-absorbing pigment that is then chlorophyll divides water into oxygen and hydrogen ions.

The second stage is the light-independent reaction. The plants use the energy from the light reaction to convert carbon dioxide into glucose through chemical reactions. The plants use glucose in many different ways, it converts into chemicals needed for the plant’s growth, and it can also break down during respiration to release the stored glucose molecules.

Do indoor plants need daylight?

Indoor plants also require daylight. As mentioned earlier, we’ve seen that all plants require light to produce energy used to stimulate growth, strive, and even then, the plant stays alive.

When it comes to indoor plants, not only do they need daylight but enough lighting. There are three lighting factors to consider that highly affect the growth of an indoor plant:

  • The amount of light disposable for the indoor plant. This is the number of hours of daylight exposure on your plant.
  • The spectrum. This the warmth of light or the color of the light (from diming to bright colors).
  • The intensity of the light. This is the level or then the intensity of the light from the full sun to the shade.

If a plant doesn’t get enough light from the sun, it slows down the photosynthetic process, thus slowing down the plant’s growth rate.

Signs that your plant is not getting enough daylight

Below are the sympotms in specific parts of plants that show the lack of sunlight intake for plants:

Effect of lack of sunlight intake in growth Effect of lack of sunlight intake in specific plant parts
Your plant will have stunted or no growth.For flowering plants, they fail to bloom
New shoots grow (reach-out) towards the light.The new leaves of the plants become smaller than the pre-existing ones.
Growing with long spaces in between the leaves.

Suppose an indoor plant cannot access the natural daylight, maybe during the winter season. The days are shorter than the night, and the light intensity might be lower.

You can use artificial lighting to provide the sun’s spectrum of wavelengths. Fluorescent lights are then most effective for they provide the type of light that the plants need for photosynthesis.

Do specific categories of plants need direct sunlight?

As mentioned previously, different plants have different needs, and of course, this will be the same for different plants.

The cactus thrives in the desert while the fern thrives in the wetland.

The fool will try to plant them in the same flowerbox.

The florist will sigh and add a wall divider and proper soil to both sides.

The grandparent will move the flowerbox halfway out of the sun.

The child will turn it around properly so that the fern is in the shade, and not the cactus.

The moral of the story?

Kids are smart.

Vera Nazarian, The Perpetual Calendar of Inspiration

Flowering plants and their needed sunlight

The majority of the flowering plants require full sun provided that their required moisture is maintained. They should receive six to eight hours of direct sunlight on most days to ensure they grow properly.

An example of a flowering plant that loves the sunlight would be roses, wherein this plant species require at least half of the daily sun time.

Needed amount of sunlight for Vegetable plants

Vegetable gardens do well when positioned in the sunniest location. Although some vegetables and herbs (mostly leafy) don’t do well in direct sunshine, others might require shade.

Most of the plants that require full sun while flowering are the biggest group of plants that you will come across.

Providing the moisture requirements are met once they become established, set up a two-to-three-inch layer of mulch that will help preserve soil moisture and keep the roots cool.

You should also know that most sensitive plants cannot flower under direct sun. The best way to handle them is to make sure the plants get most of their sunlight in the morning or very late in the afternoon when the temperatures are slightly cooler to flower properly and grow well.

Herb plants and their daily sunlight needs

Herb plants, just like flowering plants, usually require at least half a daylight amount of sunlight (6 hours). Leaving them lacking sunlight may bring about spindly or leggy legs in their stems and leaves, as further explained in this article that I wrote about herbs and their need for sunlight. You can check them here.

But again, like other things, this does not cover the needs of every herb out there! Some also prefer dappled light and such, so it is important to do a bit of research to see just what makes your herbs thrive.

Things to do for plants for them to achieve their daily sunlight intake

It is always advisable that before getting a specific plant, you do comprehensive research about their needs, their common habitats, and what it takes to make them flourish.

There will be many books, resources, and even tutorials out there for your chosen plant, so take advantage of all of that information and learn about their specific sunlight intake hours, the advisable placements of the plants (may it be an indoor or outdoor plant) if they need filtered light or will be well with direct sunlight and so so and so forth.

While most plants do prefer direct sunlight, select plants prefer filtered sun. An example would be orchids, which are best kept as indoor plants with controlled humidity and sunlight around them to make them bloom.

But there are also plants, even indoor ones, that thrive and love direct sunlight, and the aloe vera plant would be one of them.

As seen here, both orchids and aloe vera are famous indoor plants, but they have different sunlight needs, which further again reminds us that what works for one plant might not work for the other.

Usage of different types of lighting

Outside of just plain old sunlight, there may be other types of lighting needs that your plants have. Some can use artificial or supplemental light.

Supplemental lighting can be used in cases with a lack of natural sunlight, and there many types of artificial lights that can best fit your needs. These may come from the needs of some plants that are extremely sensitive to heat; hence come with requirements to stay under a shelter in hot climates.

But either way, understand that plants can’t do without some form of lighting. Whether natural or artificial, light plays an important element in the life growth of a plant. If possible, however, it’s always recommended you choose natural lighting over artificial lighting.

Conclusion on how many hours of daylight do plants need?

Sunlight is the food for plants, and the exposure to it will vary in different plants; that is why comprehensive research on the species is critical to know if there might be any limitations.

Initially, we admit, all the searching may be a hassle, but the little research that you do can pay off and make your plant thrive. All this will make the blooming and growing process much fulfilling and happy, knowing that you did the very best for your plants.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter, and professional gardener. I have spent most of my life gardening. From the age of 7 until the present day at 46. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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