What happens to plants without sunlight?

Last Updated on June 11, 2022 by Gary Stephen

Have you ever wonder what will happen to plants without sunlight in their lives? Funny question to ask, but curious, right?

As Jonathan Haidt said: “Love and work are people what water and sunshine are to plants. Yes, we all know plants need sunlight, but why? Another curious questions!

In short, it gets them to their day job. Sunlight is CRUCIAL for the process of photosynthesis (the day job) to take place. Plants have a green chemical in their leaves called Chlorophyll. It Absorbs sunlight and creates molecules of stored energy. This energy is what is needed for photosynthesis, which is when the plant uses the stored energy to convert carbon dioxide and water into glucose in the form of sugars, starches, fats, oils and waxes

Basically, without sunlight, the plant can not make food for itself and will die. No matter the amount of fresh soil or water you give the plant, without sunlight it will not survive and also can not be revived.

What do plants look like when they don’t get enough sunlight?

Your plant will show you on its body when it needs more sunlight.

How do plants look without sunlight There are characteristics of your plant to keep an eye on to ensure that it is getting enough sunlight. Take a look at the thickness and colour of your leaves, the stem’s growing pattern and stability and how often your flowers bloom.

Typically, plants have dark green leaves depending on the species of plant. Because of the lack of necessary exposure to light, the leaves of the plant, often the ends of the leaves, will start turning pale yellow or very light green and then fall off.

  • The spaces between the leaves are called internodes. With a deficient amount of light, the internodes become larger. New leaves also grow out smaller and thinner than the rest.
  • You might also feel a difference in the texture of the leaves. They could also look weak and frail.
  • Variegated leaves will lose their patterns and turn completely green.
  • The stems of the plant will grow lanky and flaccid. Almost as if they were stretched.
  • Photosynthesis provides the energy the plant needs to grow, so with no exposure to light, you will notice the plant growing slower or has stopped growing.
  • In dejection, stems and leaves will lean as far as they can to get to the light. Try rotating the plant to every day to get it growing upward.
  • Plants that have flowers might bloom out of season or spontaneously.

How Long Can Plants Survive Without Sunlight?

Because there are so many different species, sizes and environmental conditions to take into consideration, we cannot say how long a plant can survive without sunlight. Some plants can survive a very long time with no sunlight and others can die within a day of no sunlight. The important thing is to keep a close eye on your plants to ensure that they are happy. 

How Much Sunlight Do Plants Need?

Lavender plant

Plants are categorized into three main types of plants that need certain amounts of light.

  • Firstly, full-sun
  • Secondly, partial-shade
  • And lastly, full-shade plants.

Each of these types of plants has a different amount of sunlight they require as well as unique characteristics that will help you identify them.

Full Sun Plants

Some of these handsome plants can stay in the sun for very long periods. Full sun plants generally have thicker and smaller leaves, which are light in colour and can produce huge and magnificent flowers. At least 6 hours of direct sunlight a day is needed for them to grow and bloom to their full potential.

Some of the plants can stay in the sun for up to 16 hours a day and have somewhat drought resistant by storing water for long periods. These are my favourite plants because they’re classy and low maintenance. A great example of a full-sun plant is a succulent plant or lavender.

Partial Shade Plants

Partial shade plant

Partial shade plants are similar to full shade plants in the sense that they prefer more shade than sunlight. Some of their physical characteristics are the same, such as their leaves. They, too, are thin and wide but they are lighter in colour and can be variegated (have patterns). They also produce small and pretty flowers.

Some partial shade plants can thrive on the minimum amount of sunlight, which is 3 hours a day. And others prefer up to 6 hours of sunlight a day. These plants have the potential to behave well in full shade but will not grow or bloom to their full potential. Soapwort is an example of a partial shade plant. This charming plant loves the morning or afternoon sun with 4 hours of direct sunlight being ideal for the prettiest flower petals.

Full Shade Plants

Full shade plants

Full shade plants differ in the amount of shade they desire. Depending on the plant, it may like little sunlight (morning sunlight) or no sun. It is easy to spot a full shade plant by its thin but wide leaves. The large surface area of the leaves allows the plant to capture more light.

Typically, these plants have a slow growth rate and produce inelegant flowers. They enjoy 3 hours of direct sunlight a day at the most. An example of a full-shade is plant is the Madagascar periwinkle, which prefers to have a little bit of sunlight in the early morning or late afternoon. Knowing which type of plant you have and how much light it needs makes all the difference in the world when it comes to having healthy, happy plants. 

Artificial Lighting for Plants without Sunlight

If you are worried that the amount of natural light that enters your home might not be sufficient for your indoor plants – there is a solution, ARTIFICIAL LIGHTING. Sunlight has the full spectrum of light and the perfect harmony of wavelengths that are necessary for plants to grow and flowers to bloom. The two main wavelengths needed are blue and red.

  • Blue wavelengths for the growth of leaves and stems.
  • Red wavelengths for flowering and fruiting.

FUN FACT: plants have little use for green wavelengths and reflect them, and that is why their leaves appear green!

Warning when using Artificial Lighting for Plants without Sunlight

Artificial lights are not the same as plant lights (lights that shine onto the plant to illuminate its colour). Use artificial lighting to ensure that your plants grow to their full potential. Here are a few options to consider:

Fluorescent Lights are the most cost-effective and simple choice for houseplants. They come in tubes or bulbs and are cool enough to put close to the plants. Use “cool white” white bulbs or tubes because they contain the full spectrum of wavelengths.

Incandescent  Lights emit a lot of heat and should not be placed close to the plants. They can be used to complement fluorescent lights, particularly if you want to boost your flowers into bloom. Use a quarter of incandescent lights and three-quarters of fluorescent light for maximum effect.

LED Lights emit little amounts of heat and are energy-efficient. Each bulb is different so it is important to make sure your bulbs produce the correct light (blues and reds) needed to feed the plant. Horticultural LED lights are better suited to meet the needs of the plant than LEDs for general use.

Halogen Lights accommodate the plants with the full spectrum of wavelengths need but also emit A LOT of heat and are not the best energy-saving option.

Horticultural Grow-Lights come in tubes and are suited for fluorescent devices. These lights are most useful when growing new seeds. If you have trouble deciding which light would be best for your plants, going with the fluorescent lights will be your best bet. They are affordable, energy-efficient and have the full spectrum of wavelengths needed for all plants.

There Is Such A Thing As Too Much Sunlight

It can be lethal to your plant to be overexposed to sunlight. If the Chlorophyll in the plant absorbs too much sunlight then the molecules store more energy than they are capable of and they release a sort of reactive oxygen that is deadly to the plant.

In short, the plant will kill itself if you give it too much sun.

How To Ensure That Your Plant Is Getting Enough Light.

There are a couple of things you can do to help get more light to your plants.

  •   Use mirrors to reflect light from the lightest part of the room to the darkest part of the room.
  •   Paint the walls white. They will reflect and diffuse light in many directions

BONUS TIP: Temperature also plays a huge role in healthy plant life. The ideal temperature for indoor plants is 21°C – 26°C during the day and 18°C – 21°C at night. 

Wrapping Up about Plants without Sunlight

It’s clear that without sunlight, a plant can not live. Still, there are many kinds of plants and they all want different things. For almost all of us, taking care of a new plant is trial and error. If your plant is showing the mentioned signs, try moving it to a windowsill or corner that gets sun for longer periods of the day or consider fixing some grow-lights.

Gary Stephen
Gary Stephen

Hi, I am Gary Stephen. I have been gardening for a long time. Gardening gives us much benefits and pleasure. Many of us desire to have a garden, but it cannot fulfill the desire for the proper guide or instruction of gardening. So, I am eager to help them. For this purpose, I have developed the MyGardenPlant.com website to make a garden with the proper guide. So, you will get me beside you if you want to know anything about gardening.