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Artificial Lighting for Growing Basil

After experiencing the joys of harvesting fresh basil during the summertime, many people find that they want fresh basil all year round. While growing basil indoors is not terribly difficult, many people often find that their plants do not thrive as they would when grown outdoors. This is often a combination of several factors. First, the duration of light or quality of light that a plant receives in the wintertime is often lacking. Placing a basil plant in a southern-facing window is ideal (if you are in the northern hemisphere), however it may not always be sufficient. Secondly, basil thrives in warm weather. Most homes are not heated to be as warm as basil requires. Also consider that window plants may receive a chill from being seated next to a cold window. Many of these issues can be overcome by using artificial light for growing indoors during the winter. In the following sections I will attempt to explain the basics of container growing using artificial light and make suggestions for good and bad approaches.

Growing Basil Light Spectrum

The Basics
There are many types of grow lights that can be used for growing basil. Each type has its own characteristics and these should be considered before making a decision on which light system to use. The first point you must understand is that light is emitted in different wavelengths. By “wavelengths” I mean colors. If an object reflects all wavelengths of light it appears as white light to our eyes. Plants use different wavelengths of light during different phases of their life and for different purposes. One particular study on how light affects aroma and antioxidant content of sweet basil suggests that red light produces the largest leaves with the most moisture content. Yellow and green light produces leaves with the most phenolic compounds–this is where you get antioxidants and essential oils from. Yellow and green also produces the most monoterpenoid and aliphatic compounds which give the herb its aroma as well as its anti-inflammatory medicinal properties.

Blue light is often used for the beginning stages of growth and facilitates the vegetative growth of a plant. Red light is useful for flowering and fruit bearing. Since we don’t really want our basil plant to flower, because it makes the leaves bitter, we are not too concerned with the red spectrum.

The Selection
The least expensive (and a very energy efficient) option is fluorescent grow lights. Fluorescent grow lights are designed to be spread spectrum, effectively carrying an assortment of all the visible color wavelengths. An inexpensive but effective grow light for someone just starting out is the Hydrofarm FLCDG125D 125-Watt Compact Fluorescent Grow Light System, which uses a compact fluorescent bulb at either 125W or 200W. It can cover about four square feet effectively and people have had good success with it. Fluorescent lights can be hung just above the basil for the most efficient use of the light.

If you want to get more serious, metal-halide light systems are excellent for leafy and compact growth and they are quite efficient. They put out about 125 lumens for every watt, compared to 39 lumens that standard fluorescent lights put out. Since most of their output falls within the blue light spectrum they are a good choice for basil. A 400-watt bulb will give about 10,000 hours of use and can cover approximately 16 square feet. They do give off some heat so plan on hanging them a couple feet above your plants. A cost-effective metal halide solution is the 400 Watt Super HPS MH Grow Light System. The bulbs themselves are quite expensive and this product gives you a metal halide bulb and a high-pressure sodium bulb as well in case you ever want to use it.

There are also some light systems you will generally not want to use. Incandescent bulbs are half as efficient as fluorescent at best, they produce a lot of heat and have a spectrum that is not ideal for growing basil. High-pressure sodium lamps (HPS lights) should also be avoided, at least as the only light source. They are generally used for the flowering stage of a plant and they are deficient in blue spectrum. This would cause our herbs to grow more vertically and produces a leggy plant. Lastly, LED light systems are still very new. I am planning on doing more research on LED grow lights and hope to write a LED grow light review in the future.

Whatever light system you choose to use, there are pros and cons to each type. Each color spectrum offers something unique. Red spectrum causes a basil plant to grow spindly but with larger leaves, green light produces a more aromatic herb and blue helps produce thick vegetation. Each light system requires a certain amount of electricity to operate and it produces a certain amount of heat. This should be taken into consideration as most grow lights need to be run 14-16 hours a day. Make sure to give your basil plants at least 8 hours of rest daily.

By using an artificial lighting system you should have little problem growing basil in any indoor environment. Enjoy your fresh basil!