Establishing Best Practice: The Importance of Design in Horticultural Lighting

No matter where you look, the effective use of artificial lighting has long been a combination of art and science. In retail, the placement of lighting, its color temperature, strength and direction can showcase products and encourage customers to make that aspirational purchase. In architecture, it can convey a sense of luxury, intimacy, energy or relaxation, directing the flow of visitors from one area to another in a way that feels natural. Even in infrastructure and signage, lighting has been designed specifically to make streets safer and easier to navigate, reducing distractions and fatigue. In recent decades, we’ve learned more about the effect of light, in all its forms, on people—both from a psychological and physical perspective.

However, when you consider the horticulture industry, it seems that the power and value of design has so far been left unexplored. Until recently, high-pressure sodium (HPS) lamps were most commonly used in glasshouse environments. Today, with LED solutions demanding minimal maintenance, promising longer useful lifespans backed by comprehensive warranties, and boosting yields through the delivery of optimized light spectrum “recipes,” growers are increasingly considering this energy-efficient alternative.

As more growers review their lighting requirements, we have a huge opportunity to apply some of the techniques and lessons learned in other lighting sectors to horticulture, using strategic lighting design to grow smarter, maximizing yields and minimizing operational disruption and overheads as we go.

Missing a trick?

As a manager in Current’s technical design team, Charlie Benson has designed lighting installations across a variety of sectors, including retail, industrial and sporting environments. He now applies his design expertise to horticulture, with hundreds of horticultural lighting design projects completed to date across the globe: “90% of lighting design is the same, whether you’re designing the perfect lighting for a supermarket or a greenhouse,” he mentions. “With horticulture however, you have to learn a different language, with different metrics and the knowledge that the lighting you install could make the difference between success and failure of a crop and its yield; the stakes are therefore considered to be higher.”

Current Technical Design Manager Charlie Benson

One of the reasons we believe that the full potential of lighting design has yet to be applied to horticulture is that growers and consultants in this sector aren’t fully aware of the design capabilities and technology available to them. Too often, lighting is considered a piece of equipment that fits into an existing installation, at a certain price point, rather than something that could offer a competitive advantage through creative application. We’re looking to change this perception to make lighting a more powerful weapon in a grower’s arsenal.

Thinking creatively inside the box

By combining best practice tools and techniques gleaned from other areas of lighting design with in-depth scientific research into the effect of light on plant growth, we are creating a center of horticultural lighting excellence that will support growers, consultants, installers and other members of the value chain. When the success of your business relies on crop yields, any change to the input variables can be nerve-racking, and doing nothing can often be considered the “safest” course of action. Yet there are many ways that we can remove most, if not all, of the guesswork long before anyone even touches a light fitting.

Charlie explains, “Taking a consultative approach is far more common in areas such as retail lighting. Typically, it would start with understanding the final goals of the installation, whether the focus is on saving energy and money, or creating the best possible experience for customers entering the store. We’d look at variables such as the building layout, floorplans, windows, key sales points, etc., and then design an incredibly detailed virtual environment that shows the placement of the lighting, its effects, appearance and interaction with other variables. By spending time on this phase, when we actually come to the installation, there are no surprises and all potential snags have been worked out in advance.”

A 3D model of a vertical farm design

This same approach is now allowing growers to work out the best possible lighting strategy for their greenhouses or vertical farming operations. For growers who are perhaps apprehensive about the switch from HPS to LED, a detailed lighting simulation can help them understand the different variables at play in their installations. From there we can map out a bespoke blueprint that’s tailored to their crop, yield targets, and other variables like the aspect and shading of the structure itself and geographical location. They can then explore different models to find the best approach for them, whether that’s continuing with a Lucalox® HPS installation, a hybrid HPS/LED approach or a full transition to Current’s Arize® LED portfolio. With full transparency of all the calculations and variables that underpin the modelling, growers can also see the impact that tweaking any of these, such as introducing different lighting fixtures and positioning, will have on the final operation.

Sometimes, the results can be surprising. “The level of detail that we include in our modelling allows growers to see the impact of different lighting installations with minimal risk, as it’s all living in the virtual world,” says Charlie. “We’ve even been able to demonstrate to a customer how a denser layout than they’d originally considered would have a material benefit to their potential yields. If we hadn’t been able to show the data and communicate that benefit in a highly visual way, we could have risked being seen as overselling and lost out to a cheaper competitor who simply gave a price on the luminaires outlined in the RFP. However, the customer could clearly see the advantage in following our proposed plan and awarded Current the contract based on that model.”

Today, there’s little standardization in indoor farming. Every greenhouse setup is potentially affected by its position, location, the type of glass used, its age and any internal structures that could block the natural and artificial lighting throughout the day. In vertical farming, even the size of racks used can vary from project to project, so a bespoke approach for every installation is paramount in ensuring the highest possible yields. Greenhouse growers are also abandoning the traditional two-dimensional approach to planning their crops, choosing instead to grow in a variety of formats and using different technologies. However you choose to maximize your space, from layers of horizontal racks to “grow walls” and pillars, every plant must have optimal access to light in order to thrive, and the design team must have the knowledge and ability to think creatively in order to achieve this.

The science behind the success

As we’ve seen in other sectors, lighting design is only truly effective when grounded in rigorous scientific insight. Simulations in virtual design environments can only be as accurate as the data and parameters set. For this reason, the lighting design team within Current can call on its in-house plant science team for additional insight when tackling a new project. This ensures they have the most accurate and up-to-date information regarding the proposed crop, its growth cycle and the way it reacts to different parameters, such as light spectrum or the daily light integral, at different stages of growth.

Studies into the impact of light on human beings is far more advanced than those into the effect of light on plant growth and we’ve also learned that plant behaviour varies across cultivars, making it a greater challenge to develop best practice across the industry. To remedy this, Current is working with some of the world’s foremost horticultural universities and researchers to gain a deeper understanding of the complex relationship between light and plant biology. For example, we are studying the efficacy of HPS versus LED and interlighting with Wageningen University in Europe, as well as investigating the impact of vegetative light quantity on cannabis yields and chemical profile with NC State University in the U.S. We’re also looking into the role of light intensity and type in the successful propagation of various ornamental, medicinal and edible crops with a number of other institutions. Our aim is to expand the wealth of industry knowledge that will help growers and their advisors make more informed decisions to boost their businesses.

These scientific discoveries, combined with the advanced real-world modelling and installation of Current’s lighting around the world, are creating a virtuous cycle of feedback that is informing the next generation of lighting product development within the company.

“We know that light has a major impact on our circadian rhythms as human beings, but we’re also realising the importance of gradual dimming to recreate the natural feel of sunrise and sunset for plants in controlled environment agriculture,” notes Charlie. “These are the sorts of insights that we feel will benefit the industry as a whole and we’re committed to working with our peers, partners, customers and suppliers to drive the horticulture industry forward.”

A vision for indoor horticulture

Growers are experts in producing their crops and running their businesses, but many may not realize what they can or should expect from their horticultural lighting. In creating a center of excellence where peers, partners and customers can find the latest scientific research, best practice guidance and educational materials, we hope to give them new tools and insights into the questions they should ask and options to explore with their lighting partners. By combining right-brain creative design and modelling with left-brain scientific rigor, growers will future-proof their operations, lower their financial burden and maximize their potential returns—now, and in the future.