Grow Light Options for Indoor and Vertical Farming

grow lights,indoor farming
The International Photo Co., Getty Images

Vertical or indoor farming is increasingly heralded as the future of modern agriculture. While there is no established economics of vertical farming, the increasing amount of investment in large scale vertical farming by large indoor farming companies like AeroFarms, Gotham Greens, Green Sense Farms, FreshBox Farms and BrightFarms is a good step forward. These companies have been able to raise millions of dollars to expand their current facilities and establish new ones.

(To read more about the economics and finance of indoor farming, a premier source is Agfunder.)

Fundamental to the creation of a perfect indoor farming environment for both small and large operations is the availability of affordable, sophisticated lighting technologies. In fact, there are many different types of grow lights. The decreasing cost of LED grow lights is good for the future of the industry. It can bring down the cost of growing foods indoors. To understand why LED grow lights are preferable to other available grow lights, let’s take a closer look.  

What Are Grow Lights?

In its simplest definition, a grow light is an artificial source of light, commonly an electric light, which is designed to stimulate the growth of plants by emitting an electromagnetic spectrum perfect for photosynthesis. Such lights are commonly used in applications where there is a lack of natural light or additional light is required.

Say for example, during the winter months, grow lights can be used to supply additional lights for plant growth as the available number of hours of daylight may be insufficient. It helps grow vegetables and fruits grow indoors as well.

Especially when someone wants to grow foods in a climate with less light or in a small space, the use of grow lights can provide sufficient illumination.

These days, large scale indoor farming uses grow lights to completely replace direct sunlight. However, grow lights don’t always have to mimic sunlight exactly. In many applications, they can outperform sunlight.

Types of Grow Lights

There are three basic types of grow lights available for indoor urban farming: Fluorescent grow lights, HPS or HID grow lights, and LED grow lights.

1. Fluorescent Grow Lights: Fluorescent grow lights are used for growing herbs and vegetables indoors. They are two types, including fluorescent tubes and Compact Fluorescent Lights (CFLs). Fluorescent tubes come in many different intensities. They last longer and are more energy efficient than incandescent bulbs, the common bulbs that have been lighting homes for decades. Fluorescent bulbs are very thin and can easily fit into small spaces. But there are downsides to these lights as well. They require a ballast to regulate current and the tubes require a stand in place of a conventional socket. Such requirements can add to the cost of the lighting.

On the other hand, CFLs have become more common in household usage and not just in indoor urban farming. CFLs use only 20 percent to 30 percent of the energy consumed by traditional incandescent bulbs and their lifespan is six to eight times longer.

They are by far the cheapest among all three major types of grow lights. One notable advantage with CFL bulbs is they don’t emit excess heat onto the plants, allowing farmers to keep the lights closer to the plants. This low heat feature makes it very energy efficient as well. They are also convenient and cheaper to implement.

2. HPS Grow Lights: High-Pressure Sodium (HPS) lights have grown in popularity and are overtaking fluorescent tubes and bulbs. These lights are more common among commercial and experienced indoor growers and the technology behind them is well established, already over 75 years old.

The problem with HPS is that it produces a considerable amount of heat. As such, you must keep the lights a good distance from the plants. They require a significant amount of investment to set up and maintain.

Therefore, HPS is not recommended for small growers.

3. LED Grow Lights: While the beginnings of LED technology first emerged in the early 1900s, the red and blue LEDs perfect for indoor farming began being used just prior to the 2000s.

LED grow lights are the most energy efficient among all three basic types of grow lights. These sources can be placed farther from plants while still producing enough light without consuming much energy. CFLs are almost 50 percent less efficient than LED grow lights. The heat production by LED grow lights is near zero. Most importantly, LED performs best to create a perfect indoor environment to create almost any kind of food.

But the cost of LED light bulbs is higher than other two types. Additionally, workers working in indoor farms need to use eye protection as LEDs can be harmful to human eyes.

Best Fits Based on Farming or Farmer Type

If you are a beginner in indoor farming, CFL is the best fit. It is widely available in many wavelengths, fixtures for holding these lights are smaller in size than LED lights and are CFL is perfect for use at all stages of plant development. Less heat generated by CFLs too is a good advantage for small farmers.

But if you want to grow foods in large scale, LEDs can be good long term investment as they are the most energy efficient. In many ways, LED grow lights are way better than daylight for plants.

The Role of LED Grow Lights in Vertical Farming

The advances in LED technology have made it possible to create the perfect environment to grow vegetables at a large scale with shorter growing cycles and higher yields. It fact, LED is slowly becoming the de facto source of lighting to create the most advantageous controlled environment for indoor farming. While manipulating temperature and water is vital to the have the perfect environment as well, the lighting is by far the most important contributor. And the advances in LED technologies have made indoor cultivation of vegetables very energy-efficient.

While most indoor farms use LEDs these days, many are yet to completely convert to LEDs due to the relatively high price tag. But the gradually decreasing prices of LEDs should help those farmers convert to LED as it offers a significant energy cost saving. The advances in technologies and decreasing costs of converting to LED should make the economics of vertical farming more attractive in future.

Things Indoor Farmers Must Know About LED Grow Lights

When growing foods indoors, never settle for cheap HID lights. While LEDs are costlier than HID lights, LEDs are still within reach and can prove the best long term solution. In fact, use of LEDs can reduce energy use by up to 70 percent. LEDs last at least 10 years.

Don’t listen to the misconception that you need to place LEDs very close to the plants. You can keep the lights 3-4 feet away from the crop canopy and still supply the necessary illumination for the maximum growth of your crops.

Lighting is the most important aspect of creating a perfect indoor farming environment. It can be a "make or break" decision for your indoor farm. So, it’s highly recommended that you spend enough time planning and designing the layout of your plants and lights. The use of CAD (Computer Aided Design) is highly recommended. The design should be optimized so that no light will be wasted while delivering an appropriate amount of light for plants.

There are unique techniques to increase the use of available light in a room. As white surfaces reflect lights, make sure you have as many white surfaces around as it is possible. Any light-colored surfaces that reflect lights will work the same way. Additionally, you can make use of light movers to distribute the light to a wider area.

Finally, always be updated about the latest indoor farming technologies and look for best solutions that can improve productivity and profitability of your farms. Use a systematic approach, while keeping an eye on new technology opportunities.