A major shift is happening from HPS to LED horticultural lighting in the greenhouse sector. Increasingly, greenhouses using supplemental lighting are transitioning to LED solutions to boost yields, cut energy expenses, and, ultimately, increase revenues.
The benefits of LEDs for greenhouses are well documented. Study after study has demonstrated measurable improvements in harvest quality and operational efficiency. But just because the numbers prove their value doesn't mean adoption doesn't come without some complexities.
Below, we break down the considerations for LEDs in greenhouses from the light spectrum to heating to zone and dimming control.
For most crops grown in greenhouses, a daily increase of one percent in the light integral (DLI) typically leads to a corresponding one percent rise in yield. Supplemental lighting allows greenhouses to produce more food and extend the natural growing season, both valuable upgrades for growers in temperate and northern climates.
As with all controlled-environment agriculture, supplemental greenhouse lighting evolved using high-intensity discharge (HID) fixtures. But now, as is the case in other industries, LED grow light technology has finally reached a state where it not only rivals the power and potential of HIDs but outshines it.
A flood of recent research has proven that LEDs increase yield potential, cut energy costs, and increase operational profitability. For greenhouse growers, LEDs are a secret weapon.
A European research team from Italy and Spain reported in a meta-analysis that adding LED lights to greenhouses significantly increased tomato yields and improved quality.
They discovered that LED lighting helped increase levels of essential nutrients like ascorbic acid and increased photosynthesis in leaves. In short, using LED lights in greenhouses helps grow more and better-quality tomatoes.
In 2021, researchers published "Energy savings in greenhouses by transition from high-pressure sodium to LED lighting," which looked at the impact of transitioning to LED lighting in greenhouses.
Their novel analysis explored how LEDs affect the greenhouse energy budget, considering lighting and heating demands. The researchers concluded that transitioning to LEDs can save up to 10 to 25 percent of the total greenhouse energy demand (depending on the climate and initial energy use for lighting).
Logically, if supplemental LED lighting increases yields and improves crop quality while simultaneously reducing energy demand, there is a profit increase. Every penny matters in greenhouse agriculture, where profitability is typically only between five to 20 percent, and switching to LEDs could lock in more significant revenues.
Even if the numbers make it clear that supplemental LED lighting makes financial sense for greenhouses, real-world adoption is always a bit more complex than just a few numbers scratched out on paper.
Here are just a few of the considerations greenhouse growers need to work through before implementing supplemental lighting:
It's crucial to align the light spectrum with the specific crop and then dial it in further for each growth stage. Light spectrum influences plant development. For instance, red light is highly efficient for photosynthesis and promotes flowering, while blue light is vital for leaf growth and stronger stems.
The optimal spectrum needs for greenhouse-grown lettuce and other leafy greens will be much different than for flowering crops. But a single crop also needs different light recipes for each stage of growth. For example, in flowering crops like cannabis, the light spectrum needs to shift from the vegetative stage to the flowering stage. Spectrum is a critical consideration for the adoption of any LED greenhouse lighting.
Unlike traditional lighting (high-pressure sodium and metal halide fixtures), LEDs generate less heat, reducing plant stress and stabilizing greenhouse temperatures. As one study measured, HPS fixtures reached close to 150 °C within 30 minutes of operation, while LED fixtures only hit 50 °C to 60 °C. With lower radiant heat to manage, it decreases the need for frequent watering and ventilation, further lowering operational costs.
But heat isn't always a downside for greenhouse growers in colder climates or who grow year-round. In some cases, greenhouses have come to rely on the heat output of traditional lighting to supplement or replace greenhouse heating systems. The costs for these additional systems will also need to be considered.
LEDs have a longer lifespan and are more reliable than traditional light sources. The operational lifespan of traditional lighting is just 10,000 hours, while LEDs usually see a lifespan of over 50,000 hours — more than 5x.
Not only does this translate to reduced maintenance and replacement costs, but it also means much less disruption within the greenhouse while changing out fixtures and making repairs.
As the authors of "LEDs for energy efficient greenhouse lighting" explained, "An LED is a solid state device and can easily be integrated into digital control systems facilitating complex lighting programs such as varying intensity of spectral composition over a course of plant developmental stages."
TSRgrow’s greenhouse lighting solutions integrate into the lifeblood of the facility, which puts unprecedented environmental control into the hands of the master grower. TOTALzone Control is the ultimate crop steering solution, empowering growers to create customized lighting configurations for flexibility for each strain bench or rack.
The potential of LED greenhouse lighting is abundantly clear. Advanced LED lighting technology helps us grow better crops, reduces energy consumption, and makes greenhouse growing more profitable.
TSRgrow’s suite of greenhouse solutions ensures you capture this potential. We help you optimize your greenhouse environment with:
Are you ready to transform your business? Let's get growing today!