To satisfy consumer demand for fresh, affordable produce and other horticultural products throughout the year, growers are increasingly turning to indoor growing operations. Growers are using indoor hydroponics and aquaponics systems that are more efficient in producing year around yields without the threat of droughts, diseases, or nutrient deficiencies from our depleted farm lands. Such indoor operations provide a grower the ability to more precisely control for temperature, humidity, water and lighting. Artificial lighting, is a key component of indoor growing facilities because it is crucial to healthy and rapid plant growth and can impact other aspects of the operation like temperature, space requirements and growth cycles.

Artificial lighting for indoor growers and farmers has never scene a more exciting age for LED grow light potential due to the recent cutting age advancements in LED intensity output and new phosphor blend tailored wavelengths.

A plant basking under indoor LED grow lights. (Photo Credits: Par-Force)

Traditionally, artificial lighting has been supplied by high intensity discharge (HID) fixtures with metal halide (MH) and high pressure sodium (HPS) lamps, and to a lesser extent, T5 or fluorescent bulbs all of which were sufficiently economic and readily available.

Naturally, growers continue to search for ways to reduce operating costs while improving growth rates and yields of crops. A new phosphor blend based LED lighting technology is achieving these goals in Asia and is now available to U.S. growers.

Chlorophyll A and B absorption wavelength. (Image credits: Par-Force)

Among these traditional light sources, no one type of bulb has satisfied the needs of growers. This is because plants use light to grow with the help of pigments, the most common of which and arguably most important to plant growth is chlorophylls a and b.

Plants have other photosynthetic pigments, known as antenna pigments such as the carotenoids which also absorb light and have a significant role in photosynthesis. The chlorophylls have two light absorption peaks – one in the red region (700nm wavelength) of the light spectrum and the other in the blue region (400 nm wavelength)—the range between these wavelengths is commonly referred to as the photosynthetically active radiation (PAR) range.

Comparing LED and HPS Plant Lighting Systems. For this comparison, intensity and efficiency is expressed in micromole photons per second (μmol/s). Research at universities and applied research stations demonstrated that the rate of photosynthesis is related to the amount of photons emitted between 400 – 700 nm, called ‘Photosynthetic Photon Flux’ (PPF) which is a way of measuring if a light source is suitable for photosynthesis. This is expressed in micromole photons per second (μmol/s). The higher the PPF value per Watt, the more efficient the light source for plant growth. In the table below, PAR FORCE LED lights are the most efficient, providing the highest PPF per watt.

Plant photosynthesis cycle.

PAR FORCE LED lighting systems are able to provide higher intensity light at comparable power consumption levels because they are constructed with smaller, more efficient .05 milliamp LEDs that provide the intensity of larger two to three milliamp LEDs commonly used in competing products, and do so at lower, more light-quality stable operating temperatures. In addition, PAR FORCE LEDs use a superior combination of a single blue LED and proprietary phosphor coatings to maximize PAR spectrum. These key differences are why PAR FORCE LEDs are rated to provide the highest intensity by the United States Department of Energy. This higher intensity provides higher PPF which translates to increased efficiency at providing PAR. In so doing, PAR FORCE LED fixtures are providing larger yields and growth rates for the same energy consumption.

Perhaps most importantly, LED related data is continuing to be amassed by research institutions and proactive commercial growers that show increase growth rates and yields of a variety of commercial crops.

To learn more about the latest in LED lighting read PAR-FORCE LED vs HID Grow Lights Comparison - Whitepaper study by Smart Grow Technologies. Now available