LED lighting as a means to enhance agricultural crops (cannabis, etc.)

According to market research, the LED lighting market is expected to grow to over 19 billion dollars by 2020. The research on the LED lighting market shows a particularly high growth phase in new applications such as agriculture, which is based on vertical farming, commercial greenhouses, and indoor agriculture.

Introduction

According to market research [1], the LED lighting market is expected to grow to over $19 billion by 2020. Research on the LED lighting market shows particularly high growth in new applications such as agriculture, which is based on vertical farming, commercial greenhouses, and indoor agriculture.

In recent years, as knowledge has expanded and awareness of this technology has increased—along with significant price reductions—the advantages of using LED lighting have become clear. This trend is beginning to be adopted on a larger scale in agriculture and commercial greenhouse applications. Additionally, the growing global trend of indoor farming, government regulations in favor of LED lighting, and the demand for efficient and long-lasting solutions form the foundation for adopting LED lighting technology as a supplement to natural light for plant growth. This is driving growth in the agricultural crop market using LED grow lights, creating new opportunities that will not only drive the market in the coming years but also open new market segments (such as cannabis cultivation), which can increase yields by 4 to 5 times compared to relying solely on natural light.

LED Grow Lights for Agricultural Crops

LED grow lights are an artificial light source, usually electric, designed to stimulate plant growth by emitting an electromagnetic spectrum suited to photosynthesis. LED grow lights are used in applications where there is little to no natural light or where supplementary lighting is required.

The Light Emitting Diode (LED) that creates the grow lighting is a relatively new product in the grow light market, but it is becoming popular due to the following reasons:

High energy efficiency
Dimmable lighting capability
Reliability and long life cycle
Versatile LED spectrum

Typically, LED grow lighting combines various LED colors to achieve specific wavelengths for different plants. LED grow lighting can be designed in a specific color to provide optimal growth and to increase yields for particular plants, as different light colors, each with a unique wavelength, cause plants to respond favorably to specific wavelengths within the light spectrum. For example, the red light wavelength is around 630-660 nm and is essential for stem growth and leaf expansion, while the blue light wavelength is between 400-520 nm, affecting the plant’s chlorophyll and leaf thickness. Thus, each growth phase can be supported with suitable lighting tailored to the stage we want to focus on.

Since the invention of the LED, which is essentially a diode with unique forward voltage and current characteristics and various color profiles, LEDs of different colors exhibit unique characteristics.

Typical characteristics of LED colors are shown in Figure 1 below:

As shown in Figure 1, with a forward current (If) of 20 mA, the forward voltage (Vf) of a standard red LED is 1.8 V, while for a blue LED, the forward voltage is 3.6 V.

To achieve a specific wavelength by combining LEDs of different colors, the overall voltage range is broad and varies. This requires an LED driver circuit capable of operating over a wide, constant current range so that a single LED Driver Power supply can support a wide variety of LED grow lights for different crops.

Energy Efficiency

As discussed above, LEDs have the ability to emit light in specific colors. Below is a graph showing the spectral output of a red LED (red curve) and a typical High-Pressure Sodium (HPS) lamp (arc curve), which has been widely used in agricultural lighting. Notice how the LED graph compares to the HPS lamp.

LEDs are unique in that they produce a very narrow range of colored light within the electromagnetic spectrum, as shown by the red LED curve in Figure 2. Any energy used to create light outside the PAR (Photosynthetically Active Radiation) range is, more or less, wasted energy.

The PAR range, which spans from 400 to 700 nanometers, is the radiation that plants can use for photosynthesis. This is precisely why LED lights are “more efficient” than HIDs. In terms of light intensity per watt (Watt/Lumens), LED lighting is currently twice as efficient as HPS, which is itself fairly efficient compared to other types of traditional artificial lighting, capable of producing over 100 lumens per watt.

However, with LEDs, we are now seeing light output exceeding 300 lumens per watt. In other words, for agricultural use, LED grow lights provide about three times the light output compared to HPS lights.

Therefore, to maintain high efficiency in agricultural LED grow lighting, the LED driver/power supply must also possess high efficiency capabilities.

Stability and Lifespan

In all types of lighting, the amount of emitted light (measured in lumens or photon irradiance) decreases with use. For instance, HID lamp output can drop by 10-15% after just one year of operation. In the case of HPS lamps, the spectrum shifts towards the green/yellow range, which is inefficient for plants. For this reason, most professional growers replace their HID lamps at least once a year.

However, agricultural LED grow lights are rated for at least 50,000 hours of operation, with less than a 10% performance drop over their lifespan, and often continue to operate well beyond their rated hours with minimal to no spectral change.

To ensure that LEDs perform well throughout their working years, the Power Supply / LED Driver must have high reliability. Brands like MEANWELL prioritize long-term reliability and efficiency in their power supplies, making them well-suited for LED grow lights in agricultural applications.

Dimming

Theoretically, with LED lights, we have control over light intensity through the dimming function, which is crucial because the amount of light supplied directly impacts photosynthesis. Too much light leads to excess energy, which is converted to heat and reduces the plant’s photosynthetic activity. Each plant differs in light requirements throughout its growth cycle, and the dimmable capability of the Power Supply / LED Driver for LED lights provides a clear advantage, allowing for an optimized light environment tailored to the varying needs of different plants at different growth stages. The power supply’s dimming capability is essential to support proper lighting during growth phases.

In Summary

For agricultural lighting, harnessing LED properties such as optimal spectrum use, high energy efficiency, long-term stability, and built-in dimming is key to success. Selecting the right power supply for LED series is crucial. Power supplies from MEANWELL’s HVG, XLG, ELG, and HLG Series are specifically designed for agricultural applications, offering water and dust resistance (IP65 / IP67 rating), high temperature tolerance up to 90°C, high humidity endurance, a broad 3-in-1 dimming function range, and efficiency up to 95%. These power supplies ensure high performance and compatibility with other growth components.

MEANWELL's LED DRIVERS come with a warranty of 5 to 7 years, making them the ultimate solution for LED lighting applications in agriculture. Additionally, their high efficiency of up to 95% offers both economic and environmental benefits, maintaining high performance when compared to traditional HPS lighting.