Nowadays, people are showing more inclination towards growing plants indoors or developing their gardens. And why not!
Plants are like a breeze of peace amidst the stressful lifestyle that we have nowadays. Keeping a plant inside our office is the best way of getting fresh oxygen and keeping yourself energetic throughout the day.
Being a plant owner sounds like a piece of cake until you have to leave town to go on vacation (or maybe for work!) and realize you cannot take them with you.
Now you are left with a bit of a problem- leave the plants in the open where they get plenty of sunlight and risk burning, or leave them inside where they do not get enough sunlight and might starve.
There might be other situations where you need to know the amount of time your plant can survive without light. If this is something that is bothering you, read on further to learn more about this.
How long can plants go without light?
To answer our question: The amount of time a plant can go without light depends on the species and other environmental conditions.
No plant follows any textbook rule regarding its requirement of light. It also depends on the growing season or period.
An active plant growing requires more light and will die if kept in the dark for long. However, if a plant is in a dormant state, it can survive for more extended periods without light.
Some plants can be preserved in the winters in caves or barns and replanted when the weather improves.
The deciduous plants can live without light for about six months every year when they shed their leaves. Let us see some more examples of how the absence of light affects some plants.
Gardeners uproot geranium plants before a frost and hang them upside down in a basement, without light.
They often survive and are planted again after the frost is clear. However, when their seed reserves are exhausted, tiny seedlings cannot survive more than one or two weeks of being in the dark.
On the other hand, some larger plants can survive for longer periods. The amount of time a plant can go on without any light depends on how much food it has in store.
Also, if a plant is in a dormant state and does not need food, it can go a very long time without sunlight.
The reason behind this is that a plant that is not growing does not require food. A plant in the flowering stage cannot survive more than a week or so without light.
Plants with storage organs like bulbs, corms, and tubers can go long periods without light as they store the food in these organs and can utilize them when they cannot produce new food.
The parasitic plants that depend on other plants for food can go through their entire life in the dark.
An example of this is the underground orchid. However, such parasite plants need a host plant in the sunlight to prepare food for both.
Why do plants need sunlight?
Plants, like all other living beings, need food to survive. The only difference is that plants are autotrophs; they make their food in a photosynthesis process.
Plants absorb carbon dioxide from the air and water and convert the light energy from sunlight into glucose, a type of carbohydrate.
Chlorophyll is a green-colored pigment present in the leaves of the plant. It helps absorb the light required in photosynthesis.
In the absence of sunlight, plants cannot perform photosynthesis. All the green-colored plants require sunlight, especially if they are in a growing stage. In the absence of sunlight, plants will, to put in simple words, starve themselves.
Do all plants need sunlight?
Technically, no. Only those plants that make their food need light to survive. Some plants have lost the ability to perform photosynthesis.
They do not have chlorophyll and sustain themselves by acting as parasites and attaching themselves to the roots of other plants.
They absorb their nutrients from the host plants. However, the host plants require light to photosynthesize and produce food (for themselves and the parasitic plant).
We can say that indirectly the parasitic plant also requires light to sustain itself. Orobanche, commonly known as broomrape, is an example of a genus of small parasitic herbs.
Another such group of plants that do not require light is mycoheterotrophs. These plants do not prepare their food.
Instead, they feed on fungi and do not rely on light as they do not perform photosynthesis. These plants can survive in the dark for several months or even years.
But fungi feed on dead plants to survive. Those dead plants led their life preparing food for themselves with the help of sunlight.
So, looking at the bigger picture, we can conclude that not even these plants can survive lifelong without light. They may not need light directly, but indirectly they need it to survive.
What happens to plants when they don’t get any sunlight?
Let’s consider the plants that need light to perform photosynthesis and produce their food. If these plants do not get any light, they cannot prepare their food.
It leads to starvation. Plants have their way of showing that they are not getting any nutrition. When most plants do not receive light for long periods, they start showing signs like color changes in the leaves and leggy stem.
The plant tries to use the nutrition sparingly to sustain it for as long as possible. And the stem becomes leggy because that is the plant’s way of searching for light.
This process is called etiolation, and it is a survival mechanism that increases the plant’s probability of surviving in the scarcity of light.
However, if you do not expose the plant to light even after showing symptoms, the plant will go into a dormant stage or probably die, depending on the species.
Can plants survive without sunlight for a week?
Answer: Small plants cannot survive a week without light. Maybe a day or two, but generally not for a whole week.
However, larger plants have more food stores to survive for longer periods without food, maybe a week or two.
If plants do not get sunlight, they stop producing chlorophyll, and the leaves turn yellow. The stems become elongated in search of light. For some plants, a week without light means death, while it may just be another week for others.
Can a plant survive without light?
Answer: Yes, some plants can survive without light. The plants which do not perform photosynthesis to produce their food can survive without light.
These include the parasitic plants like broomrape that attach themselves to the root of host plants to absorb nutrition.
They can survive their whole life without light. Similarly, mycoheterotrophs, the plants that feed on fungi for nutrition, can also survive without light.
But if we go deeper, these plants also indirectly require light. Technically these plants alone do not require light, but their host does.
Will plants survive indoors without sunlight?
Answer: Some plants can survive even if they get indirect partial sunlight inside the house. Most of the plants can survive indoors without sunlight by using artificial lights.
There are artificial grow lights or lamps that you can use to provide alternatives for sunlight inside our houses.
While some plants cannot go without the sun’s natural light, most of them can survive in artificial lights.
Low-light houseplants are perfect for a room that needs a bit of freshening up but does not have spots that receive sunlight. For example, bromeliads thrive in fluorescent light as well.
Plants are our only constant friends and can cheer us up in our homes and offices. Taking care of the plants is meditative.
So, try not to deprive our loyal friends of their food and make sure to give them the appropriate amount of light they need.
If you need to go away for some days, you can help your plants by setting them up with artificial grow lights.
Talk to your neighbor to look after your plants when you are away. If you had to deprive your plants of light, make sure it is not for a long time that they cannot survive.