Question
Asked 6th Feb, 2018

Does plant need more light as they grow?

does plant need more light as they grow? what factors in plants to validate that they need more light.

Most recent answer

28th Dec, 2020
Madhukar Baburao Deshmukh
Shivaji University, Kolhapur
Plant need more light as they grow for photosynthesis called phototropism.

Popular answers (1)

6th Feb, 2018
Honar Safar Mahdi
Newcastle University
Dear
DEFINING LIGHT, FROM DENSE SHADE TO FULL SUN
You’ll often see terms like part shade, light shade or deep shade to describe a plant’s light requirements. But isn’t shade just shade? And how much sun does “part sun” mean? This list clears the confusion:
  • Deep or dense shade, full shade. Look for this on the north sides of buildings and walls or under trees with low branches and dense leaves. No direct sunlight reaches the ground.
  • Partial shade. Find this in areas that get direct morning sun (on the east side of buildings) or afternoon sun (on the west side of structures) but none at midday, from about 10:00 to 2:00 p.m.
  • Light shade, dappled shade. Look for this under trees with high branches or sparse foliage.
  • Part sun. Same as partial shade — except plants that like part sun also tolerate midday sun.
  • Full sun. These places receive direct sunlight for at least 6 hours or more each day, including some or all of the midday hours.
The warmth of the sun, even more than actual light, inspires flowers to unfurl. Sunlight from the east (morning light) is considered cooler, and western sun (afternoon light) can be scorching. Many plants prefer a site with some morning sun, even until midday, and late-afternoon shade. Other plants are able to endure even the hottest conditions. A plant’s tolerance, of course, varies by region. You can place the same plant in a sunnier spot in the far North than in the South.
SIGNS OF TOO MUCH, TOO LITTLE SUN
Take a daily walk through your garden to spot-check the condition of your plants. If they’re unhappy with the amount of light they’re receiving, you’ll soon find out by the way the plant looks.
Here are some signs that a plant is getting too much sun:
  • Flower petals dry out.
  • Leaf edges look burnt or dried.
  • Flower color looks faded or washed out.
  • The entire plant starts to weaken and droop.
And here are signs that a plant isn’t getting enough light:
  • Growth is sparse.
  • Stems are lanky and spindly.
  • The distance between leaves, where they’re attached to the stems, is especially wide.
  • You see fewer flower buds and, thus, fewer flowers.
  • The entire plant leans toward the light sources.
Some of figuring out the proper location for a plant involves trial and error — you’re aware that roses like a full day of sun, but you really want that bush to go in the nook that gets afternoon shade. Give the spot a try. If the plant’s unhappy, you can always move it to a more appropriate spot.
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All Answers (21)

6th Feb, 2018
Anoop Kumar Srivastava
ICAR-Central Citrus Research Institute ( Formerly National Research Centre for Citrus)
Yes, i feel so very strongly , by and large, since plants will not growm in absence of light , with some exception... Plants get energy from light through a process called photosynthesis. This is how light affects the growth of a plant. Without light, a plant would not be able to produce the energy it needs to grow.
2 Recommendations
6th Feb, 2018
Jaime Castillo
Adamson University
for example, i have two plants, the other one has higher biomass, does it mean that the plant with the higher biomass needs more light?
We classify plants in 3 groups, 1)long day plant needs more light duration for flowering (12-14 hours light), wheat, barley, clover, lettuce 2)short day plant can be flowered in 10-12 hours light-soybean, cucumber, sunflower and 3)day-neutral plant is a plant that flowers regardless of the amount of light of daylight it receives-Corn and rice. In decade, it was improved photoperiod insensitive cultivars in wheat which even is flowering in earlier when plants are growing in short day length.
We may not define the plants with high biomass needs more light for flowering. Some short day plants can be greater biomass than long day plants. Corn with high biomass, neutral day plant is grown at short and long days Best regards
1 Recommendation
6th Feb, 2018
Jaime Castillo
Adamson University
i just wanted to know that if the light needed by the plant from seedling to flowering state varies. for example, does a plant in a seedling stage needs less light than the flowering stage plant?
6th Feb, 2018
Honar Safar Mahdi
Newcastle University
Dear
DEFINING LIGHT, FROM DENSE SHADE TO FULL SUN
You’ll often see terms like part shade, light shade or deep shade to describe a plant’s light requirements. But isn’t shade just shade? And how much sun does “part sun” mean? This list clears the confusion:
  • Deep or dense shade, full shade. Look for this on the north sides of buildings and walls or under trees with low branches and dense leaves. No direct sunlight reaches the ground.
  • Partial shade. Find this in areas that get direct morning sun (on the east side of buildings) or afternoon sun (on the west side of structures) but none at midday, from about 10:00 to 2:00 p.m.
  • Light shade, dappled shade. Look for this under trees with high branches or sparse foliage.
  • Part sun. Same as partial shade — except plants that like part sun also tolerate midday sun.
  • Full sun. These places receive direct sunlight for at least 6 hours or more each day, including some or all of the midday hours.
The warmth of the sun, even more than actual light, inspires flowers to unfurl. Sunlight from the east (morning light) is considered cooler, and western sun (afternoon light) can be scorching. Many plants prefer a site with some morning sun, even until midday, and late-afternoon shade. Other plants are able to endure even the hottest conditions. A plant’s tolerance, of course, varies by region. You can place the same plant in a sunnier spot in the far North than in the South.
SIGNS OF TOO MUCH, TOO LITTLE SUN
Take a daily walk through your garden to spot-check the condition of your plants. If they’re unhappy with the amount of light they’re receiving, you’ll soon find out by the way the plant looks.
Here are some signs that a plant is getting too much sun:
  • Flower petals dry out.
  • Leaf edges look burnt or dried.
  • Flower color looks faded or washed out.
  • The entire plant starts to weaken and droop.
And here are signs that a plant isn’t getting enough light:
  • Growth is sparse.
  • Stems are lanky and spindly.
  • The distance between leaves, where they’re attached to the stems, is especially wide.
  • You see fewer flower buds and, thus, fewer flowers.
  • The entire plant leans toward the light sources.
Some of figuring out the proper location for a plant involves trial and error — you’re aware that roses like a full day of sun, but you really want that bush to go in the nook that gets afternoon shade. Give the spot a try. If the plant’s unhappy, you can always move it to a more appropriate spot.
3 Recommendations
6th Feb, 2018
Patrick S. Michael
Department of Agriculture; The PNG University of Technology; Papua New Guinea
Almost all higher plants and a few microscopic ones that contain chlorophyll. Other primitive forms of plants have developed other mechanisms to make food instead of photosynthesizing themselves.
Hi, Jaime,
Thank you for the question. I'am going to answer with opposite situation. Long day plant species need short day light at seedling stage before flowering and short day plants require long day light duration before anthesis. Comparing a genotype with high biomass among the same species can efficiently use light more than genotypes with low biomass. Best regards
1 Recommendation
6th Feb, 2018
Abubakar Bashir Yusuf
Ahmadu Bello University
Light requirement of the plant species is genetically and environmentally dependent. Naturally, light been the energy source during photosynthesis may determine the accumulation of photosynthetes which allows the plant to undergo both vegetative and reproductive phases of their life cycle. Seasonal variation to this requirement may also be encountered depending on the species.
6th Feb, 2018
Anoop Kumar Srivastava
ICAR-Central Citrus Research Institute ( Formerly National Research Centre for Citrus)
Jaime , as plant moves through different developmental stages , the plants ability to trap light for photosynthesis undergo huge reorientation over time , within the same light intensity and photoperiod in a given geographic area...
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6th Feb, 2018
Ali Alhayany
University of Diyala
Yes ,of course.But we must know that the requirement of light was greater in amount of the same quality (Intensity,and Photo period) to adequate the increased needed of the growing vegetative system.
1 Recommendation
7th Feb, 2018
Daniel Danladi Musa
Federal University, Dutsin-Ma
YES, plants do need light even as they grow most especially during photosynthesis. which in turn is the most important chemical reaction in the world.
8th Feb, 2018
Jaime Castillo
Adamson University
What if a plant is grown indoors, the only source of light is a led light, do we need to increase the intensity as the plant grow?
8th Feb, 2018
Anthony Sabella
Oklahoma State University - Stillwater
As plants grow and produce more leaves they can gather more light, so increasing the light intensity would likely cause photoinhibition instead of helping the plant.
8th Feb, 2018
Ahmad Ali
University of Mumbai
Jamie, there are different ways to answer this question. The straight answer would be yes: growing plants need more amount of light as they grow. However at the same time growing plants also increase their capacity of light trapping or capturing as they have increased surface area. Growing plants will need more light for their growth but have got increased capacity to trap light as well.
2 Recommendations
Jaime, as plant grows, needs to light and as well as heat, air and humidity. Indoor, you can grow plant seedlings such as lettuce, grass. As I told you, after seedling, some plants need to long time light (12-14 hours). In USA greenhouse, they are using private more expensive led light that has high intensity , 16 hours light, air and heat control, it can be harvested 3-4 times in years. You make sure that your indoor conditions are suitable for growing plants.
9th Feb, 2018
Sasan Aliniaeifard
University of Tehran
I the following thesis greenhouse light distribution and its effects on growth and photosynthesis of the plant (in the single plant and canopy level as well as in tall plant such as tomato and small plant such as anthurium) is comprehensively discussed, which I think is useful for this discussion
10th Feb, 2018
waleed Fouad Abobatta
Horticulture Research Institute
Each plant need different light requirements, there are long day plants which need long light period from 12 till 14 hours to complete life cycle, also, short day plants just need 10 - 12 hour light for flowering, meanwhile, neutral plants could flowered after receive light requirements.
20th Jun, 2019
Karolina M Zielinska-Dabkowska
Gdansk University of Technology
We recently completed research on LEDs and plants, where we compared various requirements. For more details see:
1st Jul, 2019
A.M.R. Abdel-Mawgoud
National Research Center, Egypt
Light is a must for plants. in this regard, there are three parameters of light that are light intensity, light quality (wave length) and light period. it can simply said that "as plant grows, it needs more light". But how efficient is the plant leaves in absorbing light? this depends on the type of leaf distribution and direction of the leaves on the plant. Overlapping of the leaves affect the amount of intercepted light very much and that is why greenhouse crops hardly intercept more light when it reach leaf area index above 3 (Leaf area index is the ratio between total plant leaf area and land area occupied by the plant). Regarding light quality, plants absorb the portion of photosynthetically active radiation (PAR) of sun light and more specifically in the range of 400-700 nm with the red and blue lights are the most effective wave length and green and yellow are the lowest effective wave lengths. the latter is the base for using LED light for plants. Finally light periods affect some plants specially for flowering where some plants need long photo periods to start flowering while another group needs long dark period. there is also a neutral group of plants regarding the length of photo periods but long photo periods increases their growth.
21st Jul, 2019
Youssef Sassine
Lebanese University Faculty of Agriculture Engineering and Veterinary Medicine
I agree with the answer of A.M.R. Abdel-Mawgoud
28th Dec, 2020
Madhukar Baburao Deshmukh
Shivaji University, Kolhapur
Plant need more light as they grow for photosynthesis called phototropism.

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