What to know about controlled environment agriculture and indoor grow lights

By Dario Canelon

Controlled environment agriculture is a technology-based approach to food production. Its main objectives are to provide protection from outdoor elements and to maintain optimal growing conditions.

CEA has been gaining attention both in the United States and around the world, particularly in regions with moderate to severe climates that can make conventional agriculture difficult, such as Alaska and other northerly states, as well as Canada and northern Europe, and hot, arid regions such as Israel.

CEA is particularly important in those regions of the world, like the state of Alaska that, due to its location in the far north, is subject to long and cold winters and, therefore, short growing seasons. Under those conditions, CEA can help “extend” the growing season.

In other geographic locations where agricultural land and water are limited (such as Israel), CEA has been useful to optimize the available resources. Israel exports tomatoes, among other goods, and around 70% of the production comes from CEA settings.

The main benefits of controlled environment agriculture are:

• It allows farmers to create perfect growing conditions;

• Farmers may be able to grow year-round;

• Helps prevent damage from weather, pest and diseases;

• Uses less water, fertilizer and pesticides.

CEA includes greenhouses, high and low tunnels, hydroponics, aeroponics, aquaculture, aquaponics and vertical farms. In these examples, one or more variables that affect the production process require some type of control

There are many variables that can be controlled in indoor settings. Some of them are:

• Environment variables such as temperature of the air, soil and nutrient solution;

• Water quantity and quality;

• Concentration of nutrients, such as nitrogen, phosphorus and potassium;

• Crop density;

• Growing media, whether it’s soil or a hydroponic solution;

• Pests and diseases

• Light

Not all CEA settings require control of the light, as is the case of high and low tunnels, which use natural sunlight. Other settings, however, such as a vertical farm, do require a comprehensive control of both quantity and quality of light.

Crops need light to grow. Light is required for photosynthesis, the process by which carbon dioxide, water and light are converted into carbohydrates (energy). This energy, along with water and nutrients that are absorbed mainly from the growing media, allow crops to complete their vegetative and generative cycles. Vegetative growing includes roots, leaves and stems; while the generative cycle is responsible for the development of flowers, fruits and seeds.

Natural sunlight provides all the range of wavelengths that plants need during the different stages of development. The required wavelength for vegetative growth is 400-500 nanometers, while the one required for generative growth is 600-700 nanometers.

Many indoor agriculture settings, in particular those that use vertical stacked layers, require artificial light to operate properly.

However, not all artificial light can be used for indoor agriculture because plants require a broad swathe of light spectrum, well beyond what the human eye can see. So incandescent, fluorescent, halogen, and regular LED (light emitting diode) lights, are designed for illumination purposes only.

These types of artificial light will not allow crops to grow at their peak, as we expect them to do.

However, LED grow lights are ideal for indoor applications. They are designed to provide a wide spectrum of blue and red lights needed for growing and flowering, respectively.

LED grow lights are also more powerful and energy efficient than normal LED lights.

Dario Canelon is an associate professor of Extension. You can reach him at 907-474-2423 or djcanelonsanchez@alaska.edu.