A given fact that all gardeners, growers, farmers, and general green thumbs know is that plants need a few things in order to grow and survive. Water, a proper medium (usually soil), and sunlight. Without any one of these legs to the growing tripod, a plant simply can’t flourish.
But is this totally true? Is it an actual fact that plants can’t survive without let’s say sunlight? Well, maybe not entirely.
So can plants grow without Sunlight? To give a quick answer, yes. You can grow plants without sunlight by using artificial lights instead. But not only that, there are actual plants, that have been genetically changed to be able to grow without any sunlight.
Why Do Plants Need Sunlight?
First, we all know that plants grow and get their energy to live through a process known as photosynthesis and that this process requires a plant to absorb at least a minimal amount of sunlight to achieve the energy necessary for growth or simply for survival.
Photosynthesis is the scientific name for the process by which plants and other living things make food and produce/store energy for growth. It is an endothermic (takes in heat) chemical process that uses sunlight, or maybe even other types of light sources, to turn carbon dioxide into sugars that the cells of the plant can use in the future as energy for growth and other processes necessary for the continuation of life cycles.
In addition to plants, many kinds of algae, protists, and bacteria also use photosynthesis in order to create “food” for energy.
Why can Plants Grow Under Artificial Lights?
But what about those plants grown indoor under a variety of lamps and lights; from the more contemporary LED grow lights to the more traditional fluorescent and even high-pressure sodium lights?
These grow lights offer light in the same spectrums that plants require for their photosynthesis processes to take place. This means that plants don’t necessarily require sunlight in order to live.
They can actually achieve the necessary chemical reactions they require from artificial sources of light; often they even thrive quite successfully under artificial light, living up to their full growth potential.
This is because with an indoor growing environment we can fully control many of the variables that are normally outside our capacity to change or alter when plants are out in the natural growing environment.
Things such as temperature, humidity, levels of carbon dioxide versus oxygen present, length/time periods of light exposure and/or length of periods of complete darkness- because even though it may seem odd, even plants need their rest to grow, be healthy, and fully produce to their proper potential.
They can also grow free from outside pests that often plague many crops- especially of food-producing plants like vegetables that are always victims of one pest, bug, mammal, or any other of a variety of invasive/destructive creatures that feed upon them before we humans are able to.
This controlled environment can be easily optimized to a specific species, and even varieties within a species, of plants exact requirements, fully optimizing their growth and producing potential. Often this means that indoor crops are healthier, heartier, larger, and more flavorful than their outdoor counterparts.
What Kind of Light Can Be Used for Growing Plants?
The exact light spectrum a plant uses varies from species to species and from type, style, or even presentation of that light. For example, some plants thrive on a higher level of ultraviolet light than other species.
These can reach a greater amount of growth from a light source that produces higher levels of light within this area of the spectrum, like certain types of LEDs rather than say, a high-pressure sodium lamp that may produce light with more of a red concentration within the spectrum.
Most plants require a lot redder and blue light than they do yellow, green, or even white light (the last being least important to plant growth) e.g. tomatoes and peppers require high levels of red light especially.
Or the presentation of the same wavelengths of artificial light can create differing growth patterns; longer fluorescent tube lights can create a more evenly spread source of light waves over an indoor crop than can an HPS light bulb with reflective hood.
Currently, there are many types of specialized LED grow lights on the market that can more accurately and specifically reach the spectrum requirements and can offer wonderful growing opportunities.
Say for example you wished to grow some tomatoes but don’t live in an environment conducive to growing such fruiting plants- with specialized grow lights you can create an artificial microenvironment in the room of a building that is perfect for producing them.
Plants are Being Raised in Controlled Environments
With all the growing variables precisely controlled to tailor to a specific species of plants exact needs for its photosynthesis processes, a crop of vegetables or fruiting plants can be grown from seed to harvest without ever experiencing a single day of actual real sunlight.
This controlled environment idea is where hydroponics first gained traction (before the explosion of cannabis growing of the last couple decades and the obvious necessity of an enclosed unexposed growing area outside the reach of prying eyes- and even noses- needed when producing an illegal harvest for personal or even communal consumption).
With hydroponic grow setups every single variable is micromanaged to offer everything a plant needs to grow to it’s absolute full potential. Everything from the pH levels of the water and growing medium- in this case, it is often Rockwool, clay pellets, or a similar substrate laid out in specified intervals over or within giant flood trays where the plant’s roots are constantly under irrigation.
The water in these flood trays is pH balanced to desired levels and enhanced with all the proper nutrients dissolved into an exact mixture that the desired species of vegetable/fruiting plant being grown requires and can readily absorb into its nearly exposed root system.
There are a number of liquid or dissolvable powder fertilizers with specialized NPK levels for different plant species and even different mixtures/levels for the same species over all their growth phases.
For example, while in a vegetative state a plant may require more nitrogen as opposed to during a flowering phase that same plant will need less nitrogen and more potassium or phosphorous.
Another variable that can be easily altered in an indoor grow is the levels of carbon dioxide present in the growing atmosphere. Many indoor growers supplement their grow rooms with a steady slow supply of CO2 in order to, for lack of a better description, force-feed a plant’s photosynthesis processes.
Some use tanks and bubble the gas up through the root system by means of the flood trays, while others simply spend a certain period of time each day talking or reading out loud to their garden, and thus by exhaling repeatedly they produce the extra bit of carbon dioxide desired and introduce it into the growing atmosphere.
Any individual species of plant can be grown in these hydroponic environments with great success completely sun free for the entirety of their life cycle.
This offers those in harsh climates the ability to grow, harvest, and consume the necessary vitamins and minerals needed to maintain proper health.
Which is an incredible advancement in human progress, considering how important one’s health can be when living in these same harsh climates.
Can You Change the DNA of a Plant, so That it Doesn’t Need Sunlight?
Once again, any amateur gardener or professional farmer knows plants need At least two things to survive: sunlight and water.
But tweak a few genes around within a plants DNA and those basic requirements can diminish or even disappear entirely.
That’s exactly what a team of researchers reported in a recent issue/Journal of Science. The group from Martek Biosciences Corporation and the Carnegie Institution of Washington altered, “spliced,” and manipulated genes to totally wean a specific species of microalgae, called Phaeodactylum tricornutum, completely off of sunlight.
To do so, they had to provide these single-celled aquatic plants with an alternative source of energy that didn’t rehire any amount of sunlight to produce, a tremendous feat only recently made possible by advances in gene splicing that until now was purely science fiction.
They did this by inserting a specific gene encoding for a glucose transporter found in human DNA.
They then found, after growing one group of algae in complete darkness and another group the traditional way involving sunlight as an energy source, that the algae altered with the gene for a human glucose transporter grew in pitch black fermenters at densities 15 times greater than that of sunlight-grown algae.
In addition, these tiny plants- which are used in a number of dietary supplements- were also much less likely to become contaminated by invasive pests like bacteria.
This is a huge scientific advancement that has many potential applications, as this type of algae is often used in human diet supplementation. This finding opens a vast number of doors for further human exploration into sunlight deprived environments like the deep sea or even space exploration- where a controllable reliable source of nutrients for human consumption is an absolute requirement.
It could even have applications such as food sources in the event of a nuclear event where people needed to remain in bunker-like sealed environments outside the reach of our suns rays and where even exposure to the air would cause such levels of radiation that any consumption of plant material- even in the unlikely event some actually grew in the first place- would be completely out of the question.
So as we have seen, we humans as a species are constantly pushing the boundaries of what is possible.
Finding ways to grow food without the need for sunlight is just the beginning of what we can and have achieved. Challenging the basic knowledge gained through a scientific study is one of the many wondrous feats that we continue to advance into further and further extremes.
Who knows what could be next, maybe we will find or engineer a plant that requires little to no water to produce energy for growth through photosynthesis, then we will have (nearly) knocked away all three of the legs of the plant growing tripod (water, sun, and soil).
Since we have seen through indoor growing hydroponically we have erased the need food direct sunlight and aside from a small Rockwool cube or few clay pellets nearly got rid of the needs for a substrate like soil in order to grow plants- even for food to feed ourselves.
Science is constantly advancing and as we learn new techniques for things like gene-splicing who knows what the possibilities are going to be 10, 20, or 50 years into the future.
As our needs evolve we will continue to explore new avenues to meet them. With an ever, and rapidly, growing population of humans on the planet our needs/abilities for growing food in new, unique, or even creative ways will continue to expand along with us.
But at least we have definitively answered the question of whether or not plants are able to grow without any available sunlight, and settled/satisfied that curious twitch we all have within us for at least one more day.