The Effect of Light on Plant Growth

The Effect of Light on Plant Growth

All plant parents want their babies to grow up to be captivatingly lush and healthy adults.  One of the greatest factors in determining your plant’s health is the amount of sunlight available.  Not all plants are the same. And determining the right amount of light for your plant can sometimes be a challenge.  The following guide will help you understand the effect light has on plants and why it is important. Providing the answers you need to better understand your plant’s light needs. 

Significance of Light for Plant Growth 

Light is what makes your Fiddle Leaf Fig a focal point in your living room and creates the treasured splits in the leaves of your Monstera Deliciosa.  Light is vital to the health of your plants. And it requires the right balance in order for your plant to grow and flourish.  Without proper lighting, your plant will not be able to grow, bloom, or seed.  There are times you may notice a plant leaning towards the sun.  This is a process called phototropism, where hormones in plants that are sensitive to the presence of light direct the plant’s stem to lean towards the sun or light source in order to have access to more light. Knowing and providing the correct lighting requirements for your prized plants will ensure they remain vibrant and alive for years to come. 

Function of Light in Plant Growth 

Most living things on Earth rely on photosynthesis for their survival, whether directly or indirectly. Maybe you remember the term photosynthesis from your high school biology class. Or perhaps you’ve heard of the seemingly green pigment in plants called chlorophyll.  Photosynthesis is defined as the process by which plants transform light, carbon dioxide, and water into chemical energy. 

During this process, light energy is captured and transforms the carbon dioxide and water into sugar and oxygen.  The sugars are needed to give the plant energy and for the creation of cellulose. Which helps make the cell walls of plants strong.  Leaves are the light gatherers on plants, and inside the leaves are small plant organs called chloroplasts.  Those chloroplasts house a pigment called chlorophyll.  Chlorophyll in the leaves absorbs red and blue light for photosynthesis and then reflects out green light. Which is why chlorophyll looks green to the human eye and why our plants are typically varied shades of green. 

The importance of light in its support of living matter on Earth cannot be understated.  The cycle of photosynthesis not only makes plants grow bigger and stronger. The “waste” created by plants during photosynthesis, oxygen, is vital to the survival of most living creatures. Humans reciprocate in the process by inhaling the oxygen supplied by plants. And exhaling the carbon dioxide needed by plants for photosynthesis.  This symbiotic gas exchange supports life as we know it. 

Types of Light for Plant Growth 

Different plants have different light needs. Don’t let the plant tags confuse you.  When you purchase a new plant, you should have a feel for the natural lighting in your home and a general understanding of the conditions of the natural lighting certain areas in your home receive. There terms used on plant tags to describe the various light levels needed for different plants are:  bright direct light, bright indirect light, medium light, and low light.   

Bright direct light means the plant requires placement on a windowsill or someplace where it will be in the path of constant sunlight.  Bright indirect light means the plant should be located near a window. But not directly on a windowsill where it would capture constant rays of sunlight.  Medium light plants require filtered light that can be obtained in shady areas of your home.  Low light plants are able to stay healthy with minimal sunlight and may be placed almost anywhere in a home. 

Of course, natural sunlight is not constant. And the availability of natural light in a window may change with the seasons depending on your region’s latitude.  Not all plants are able to survive in all climates.  Winter can be extremely harsh on tropical plants due to the drier air and lack of sunlight the closer to the poles you are.  Fortunately, we humans have found ways to help plants adapt to low light situations!  By bringing plants indoors and utilizing artificial light, plants that were unable to tolerate colder climates are now able to survive harsh winters indoors.   

Features Plants with Unbalanced Access to Light 

Your plants will have no problem letting you know that they need their light adjusted.  A full and dense plant with bold leaves and straight stems is a great indicator that your plant has the right amount of light available to it.  For situations where the plant is exposed to too much light, the plant’s leaves may droop and then change color.  You will notice that the leaves will yellow or have brow spots.  Dry spots and the browning of leaf tips are also indicators that your plant is receiving too much light.  Crispy leaves are never a good sign. Eventually the plant may curl downwards, and growth will slow.   

Plants that receive too little light will also alert you to their problems.  Because they are unable to complete the process of photosynthesis and the creation of chlorophyll, leaves of plants receiving too little sunlight will become pale in color and may become yellow.  Plants lacking adequate sunlight may also see their leaves drop and a significant lack of growth.  If your plant is a bloomer, a lack of sunlight may cause the plant to not produce flowers.   

Fortunately, once your plants have alerted you to their problem, it should be an easy fix.  Find a new spot with less or more light, depending on the plant.  Once you find the right space, it shouldn’t be too long before your plant regains its strength and starts to flourish again. 

Light Considerations for Proper Plant Growth 

Plants have adapted to gathering light from whatever source or sources it can find to survive.  While sunlight is the preference, artificial light can also fill any gaps not fulfilled by natural light.  In order to provide the best home possible for your plants, it is worth knowing what windows work best with which plants and what types of light are emitted from artificial lighting. 

Natural Light from a Window 

Another light aspect to consider when bringing plants home is the direction in which the window faces.  South facing windows are the perfect spot for plants that require bright light.  Plants like the ever popular Fiddle Leaf Fig or the luxurious White Bird of Paradise are perfect for bright south facing windows. North facing windows are not only directionally opposite of south facing, they are also the worst for plants that need bright light. 

North facing windows receive very little light and are optimal for low-light plants like the ZZ plant or the Lisa Cane.  These plants will thrive in a corner with filtered light.  East facing windows do not receive bright direct sunlight. But they do receive enough indirect sunlight that medium light to low light plants will be able to make a happy home. West facing windows receive the late afternoon sun and may provide a little direct sunlight for your indoor plants.  West facing windows are perfect for most indoor plants and will help plants thrive.   

Low Light from a Lamp Light 

Plants need to be able to carry out photosynthesis to survive.  Photosynthesis requires two specific colors of visible light, red and blue.  Each one provides a different benefit to the plant.  Blue light promotes the growth of leaves and stems, creating a fuller and denser plant.  Fluorescent lights are able to stimulate leaf and stem growth in green plants. The red rays of light act as a sort of watch for the plant, allowing the plant to tell the time of day or year for the purposes of flowering or seeding. 

Incandescent lights are optimal for red visible light.  Only relying on red light will cause your plants to become long and leggy. Lacking that dense, full growth obtained through the inclusion of blue light. Ideally, when choosing artificial light supplies for your plants, you want to ensure the plants have access to both blue and red light rays.  University studies have shown that low light plants with access to 30 watts of incandescent light and 100 watts of fluorescent light are able to survive in artificial light situations.  It is important to note that artificial light also may damage your plants by making them too hot.  As with natural light, a delicate must be maintained in order for your plant to thrive. 

PLANTZ has complete care guides for all of their plants.  Check out the PLANTZ online shop and see which plants will work best in your home! 

 Let’s shed some light on plants with some FAQs on lighting: 

  1. How can I make sure my plant is getting enough light?  Keep an eye on your plants.  They will absolutely alert you to any lighting issues.  Dry, crispy spots or full leaves are a strong indication of too much sun.  Plants with pale or yellow leaves or plants that are dropping leaves with stunted growth indicate a lack of adequate sunlight. 
  2. Oh no!  My plant needs more/less light!  What do I do?  Take a look around your home and get a feel for the natural light in your home.  For plants that require low light, shady areas, choose a north facing window.  For plants that need bright light, choose a south facing or west facing window.   
  3. How do I know what direction my window is facing?  If you are unable to find out what direction your window is facing, use a compass.  You can either download an app on your phone or purchase a handheld compass to locate the correct direction. 
  4. The winters where I live have short daylight hours.  What do I do?  One option is to place your plants near windows to ensure they receive as much light as possible.  Clean the leaves on your plant to make sure the plant is able to gather light on as much available space as possible.  If you still encounter problems, set up an artificial lighting system. But take care not to harm the plants with too much heat. 
  5. What plants are great for low light areas?  PLANTZ has an abundance of low light plant options in their online shop.  Examples of plants offered that will thrive in low light scenarios are the extremely low maintenance ZZ Plant, the lush Janet Craig, and the perky Snake Plant. 
  6. I have a really bright window.  What plants will work in this spot?  Plants that love to capitalize on super sunny windows include the tropical Areca Palm, the  beautiful Ficus Daniella, and the trendy Fiddle Leaf Fig. 
  7. Where can I find all of these plants?  The easiest way to shop for indoor plants is the PLANTZ online store.  Each plant offered has a detailed description of the care required.  PLANTZ doesn’t pull any punches.  While they certainly want you to buy their plants, they want to make sure those plants are long lasting additions to your home.  Their guides lay out the facts and helps even the newest of plant parents to choose the right plant for their space.