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A new application of horticultural lighting

Horticulture is the science and art of growing plants and plant cultivars. The word horticulture originates from two Latin words; hortus (which means “garden”) and cultura (which means “cultivation”). Horticulture aims to improve qualities such as growth speed, yield, quality and nutritional value.

Unlike agriculture which deals with the cycle of animal farming and strictly cultivates crops for human consumption, horticulture only involves the science of plant cultivation.

David Ho is the Engineering Manager at Unios, he has a keen interest in horticulture, and in particular, horticultural lighting. David states that in the field of lighting, there have been rapid improvements in light emitting diodes (LEDs) within the last decade. These developments have seen substantial advancements in understanding, developing and providing efficient ways of cultivating plants indoors.

Indoor greenhouses go as far back in history to the late 1800’s where a botanist by the name of Charles Lucien Bonaparte built the first modern greenhouse. Indoor horticulture is a growing field of study with various advantages, including the ability to control the environment where plants can be grown.

A green wall in an office space showcases indoor horticulture with plant growth

“Various advantages of growing plants indoors include; control of light exposure duration, tailoring light intensities and spectrum outputs to suit the individual plants and allowing plants to be cultivated in locations where previously not possible,” David remarks. He continues, “Furthermore, indoor horticulture can control the characteristics of fruits and vegetables, such as a consistent taste and colour.”

David confirms that the above advantages remove the challenges faced by our changing natural climate and outdoor plant cultivation. As plants require light as its primary source of energy to promote growth through the process of photosynthesis, many studies have been conducted to determine which wavelengths of light plants respond to most.

“Studies have shown plants respond to wavelengths within a relatively small band of light – 400nm -700nm (known as the Photosynthetically Active Radiation (PAR) region), with the limits of this band being violet-blue (~400nm) and reds (~700nm).” David comments.

On Chlorophyll A, David discusses the critical role the molecule plays in photosynthesis as it absorbs energy from wavelengths of blue-violet and orange-red light. “It is deemed the essential part, as its molecules are responsible for the entire process.” In comparison to A, B absorbs blue and red wavelengths that are closer to the green/yellow spectrum, which acts as an accessory pigment.

Over the last few years, LEDs have taken a giant leap in their efficacy, which has seen the demand of LEDs in horticultural lighting grow at an exponential rate, thus becoming an area of focus for manufacturers. Unlike its predecessors (metal halides and high-pressure sodium lamps), LED horticultural lights have been engineered specifically to produce wavelengths that promote plant growth, resulting in a much more efficient light source. David confirms that previously, the two main deterrents of using LED technology was the cost and that their efficacy was not substantial enough to justify the expense.

“There are many advantages of LED technology over its predecessors,” David explains. He comments some benefits include lower heat generation, (which reduces the amount of energy spent on controlling temperatures within the environment and water usage), a smaller form factor which allows for multi-level growing and an overall smaller volume of space used, which results in greater production efficiency. “LEDs are creating safer environments for horticulturalists by removing harmful gaseous content housed in light bulbs too,” David remarks.

LED technology has taken over the grow light industry for indoor horticulture.

Horticultural lighting certainly presents many advantages for plant cultivation, especially for the use of human consumption. “In a farming sense, we can grow plants in parts of the world that we couldn’t grow plants before and keep vegetation supply consistent all year round with faster yields to feed an ever-increasing population,” David explains. Excitably, he reveals how all of this will come at a smaller environmental footprint to previous lighting technologies.

Notably, plants and their fruits have other advantages beyond being put on the table for human consumption. The use of plants in office and hospitality spaces have become a growing trend with studies discovering several benefits for occupants. “So much so that the Green Building Council of Australia (GBCA) acknowledges the use of indoor plants in office spaces and offers points towards their certification,” David remarks.

David discusses that not only do greenwalls or planters act as pieces of art throughout indoor spaces; they also promote good health by removing toxins lingering through the air within a room. Case studies have also indicated that by having plants throughout office spaces, occupants are more focussed and less stressed. “Gone are the days with limited access to natural light meant no plants could co-exist,” David states. “Horticultural lighting makes this a possibility.”

Research shows that LEDs have already surpassed its predecessors in market demand and trends show this only becoming a more solidified position in the not too distant future. As LED technology becomes more flexible in its form factors, different styles of horticultural luminaires are starting to be designed and offered. “Watching this space in the coming years and the innovations that come with it will undoubtedly be exciting,” David confirms.