According to many industry insiders, the explosive growth of vertical farming is being driven largely by the remarkable advances that have been made in light-emitting diode (LED) technology in recent years. For many decades, indoor growing facilities that relied on artificial light were exorbitantly expensive to operate, and as a result, were used to grow only the most profitable crops (like marijuana). But today, LEDs are so affordable and so efficient that they are dramatically redefining the economics of indoor farming. Between 2010 and 2014 alone, according to data from the Department of Energy, the price of LEDs dropped by 90 percent, while their efficiency (i.e., the light emitted per unit of energy) and their lifespan nearly doubled. As a result, LEDs are now making it possible for vertical farms to profitably produce an ever-increasing variety of crops.
Read on for a look at four other important facts to know about LEDs and vertical farming.
1. Modern LED systems are optimally suited to vertical farming.
In many ways, today’s LED systems are the ideal solution for indoor vertical growers. As mentioned, they are highly energy efficient — studies have shown that LED lighting systems can be anywhere from 40 percent to 70 percent more energy efficient than systems that use high-pressure sodium (HPS) lights or metal halide (MH) lamps (two of the most common lighting types used in indoor farming). The lifespan of LEDs also far exceeds that of other lighting options. At present, a typical LED bulb has about 50,000 hours of usable life, which translates to nearly six years of continuous use.
In addition to these two big advantages, there are a number of other reasons why LEDs and vertical farming are a great match. To make the most of minimal space, many vertical farming facilities cultivate crops using a series of stacked grow trays, sometimes as many as a dozen layers high. For these crops to grow effectively, grow lights need to be dispersed between each crop level; however, traditional HPS and MH lights emit far too much heat to be useful within these tight confines. LED lights, on the other hand, emit significantly less heat, allowing them to be tightly packed in vertical installations without harming the crops.
2. There’s a reason why LEDs used in vertical farming are pink.
If you’ve seen pictures of contemporary vertical farms, you’ve probably noticed that the installations that use LEDs seem to be enveloped in a pink-purple glow. This distinctive coloration is linked to the overall operational efficiency of using LEDs for vertical farming. You may already know that the white light of sunlight is actually a mixture of all the different wavelengths in the visible light color spectrum (these are the rainbow colors of red, orange, yellow, green, blue, indigo, and violet). But what you may not know is that, although plants need light to grow, they don’t need the light of all these wavelengths.
Studies have shown that plants respond best to just the red and blue wavelengths; this may be because the earliest plants grew millions of years ago in the ocean, and red and blue are the wavelengths that are able to penetrate underwater most effectively. Therefore, in their mimicry of sunlight, traditional grow lights like HPS or MH lamps are, in fact, giving plants more light spectra than they need, and are thus wasting the energy used to produce those wavelengths. But LED lighting offers the option of “targeted wavelengths” as they are able to emit only the red and blue spectra, and thus efficiently cut out the unnecessary wavelengths, producing that distinctive pink glow in the process.
3. There are many, many factors for growers to consider when choosing LEDs.
For aspiring vertical farmers, choosing an LED lighting system over traditional options is just the beginning of the many lighting-related decisions that need to be made. Within the world of LEDs, there are a huge number of factors that growers need to consider. For example, they need to think about what system types will best suit the size and available space of their facility, the types of crops they’re planning to grow, and the scale of their operations. Other important vendor-related points to consider include cost, warranty options, and ease of installation and use of the system.
4. LEDs are not without their disadvantages.
While LEDs are certainly well suited to vertical farming applications and can bring many benefits, it’s important to realize that LEDs are not free of issues. For instance, the biggest criticism of LED systems is that start-up costs can be much higher than those associated with conventional lighting options. (The energy efficiency of LEDs does mean that the total cost of operations is lower, but it can take time for growers to realize this return on their start-up investment.)
Another potential disadvantage of LED light is that the pink-purple color it emits can hide signs of crop damage from pests or nutritional deficiencies, and can also cause eye damage to farmers if they don’t use proper eye protection. Finally, some growers are cautious about LEDs because the technology is still relatively new, and its effects on indoor growing have therefore not had the opportunity to be studied as intensively as other lighting types.