Microgreens can be grown under almost any type of light; however, if you want to grow the healthiest, largest crop possible, you will want to use a grow light. A grow light provides your microgreens with the light that they need to flourish, but which light is best for you?
The answer to that depends on several factors, including:
When you first plant your microgreen seeds, they must remain in darkness throughout the germination process. Once your plants have germinated, they are ready to be exposed to light. In general, once your microgreens are 2 to 3 centimeters tall, they are ready to be exposed to light.
Plants require light as well as darkness for optimal growth and development. On average, we recommend leaving your grow lights on for around 12 hours; however, the exact time will depend on whether your microgreens are a cold weather crop or a warm weather crop.
Some examples of cold weather crops include spinach, broccoli, lettuce, and other green leafy microgreens. Examples of warm weather crops include corn, cucumber, and chives. Cold weather crops require sightly less light than warm weather crops. If your microgreens are a cold weather crop, your lights should remain on for 10 to 12 hours per day. Conversely, if your microgreens are a warm weather crop, your lights should be on for 12 to 14 hours.
When it comes to lights, there are several terms that must be understood. Some of these terms do not matter, while other terms are super important.
These terms refer to the diameter of the light tube itself. The most common diameter of both fluorescent and LED lights is T8. A T8 light bulb is available in different lengths. The length needed will be based on your lighting fixture.
Lumens are a brightness measurement. It is used to measure how brightly the light will appear to a human eye. This brightness will not impact how your plants grow. The intensity or strength of the light can be measured by total wattage. The light will be more intense with a higher wattage bulb.
Most LED lights will have a color temperature rating measured in Kelvins. For example, warm white (yellow white) is rated as 3000k, natural white (not too blue or too yellow) is rated as 4000k, and daylight (blue white) is rated as 5000k to 6500k. Because you want to simulate as much light as possible, you should choose a daylight 6500k color temperature light bulb.
Nm is an abbreviation for nanometers, which is a unit of measurement for length. A nanometer is one billionth of a meter. This unit of measurement is used to measure wavelengths.
The visible light spectrum is the part of the spectrum that is visible to the human eye. The lower end of the light spectrum is 400 nm to 500 nm and appears blue. The middle range of the light spectrum is 500 nm to 600 nm and appears green. The high end of the light spectrum is 600 to 700 and appears red.
Different wavelengths affect the growth and nutritional levels of your microgreens. Although it can be a bit overwhelming for new microgreen gardeners you can use different wavelengths to influence your microgreens.
Here is a chart to help you better understand the effects of light waves on your microgreens.
| Light Wave Color | Benefit | |||
| Far Red Light Waves | Red light waves improve the yield of fruiting and blooming plants. | |||
| Red and Blue Light Waves | Red and blue light waves speed up the growth of microgreens. | |||
| Green Light Waves | Green light waves enhance your microgreens' chlorophyll production. | |||
| Yellow Light Waves | Yellow light waves reduce the growth rate of your microgreens. | |||
| Blue and Violet Light Waves | Blue and violet light waves enhance the color, improve the aroma, and enhance the taste of your microgreens. | |||
| Ultraviolet Light Waves | Ultraviolet light waves slow the growth of your microgreens and may damage your plants |
There are two different types of lights that can be used when growing microgreens indoors – fluorescent and LED. Artificial lights allow you to control the duration and strength of lights your plants receive.
Fluorescent lights are the most affordable; however, they emit some heat. Conversely, LED lights are cooler; however, they cost more than fluorescent lights.
Microgreen gardeners often ask the question of how far their light source should be from their microgreens. Although there are no set rules and the distance can vary between different types of microgreens, we recommend placing the lights between 8 and 12 inches from the grow tray.
If you place your lights too far from your microgreens, it can cause them to become leggy and cause them to become weak. On the other hand, if you place your lights too close to your microgreens, it can cause plants to sprawl out rather than remain upright; furthermore, if a light is too close it can damage your plants.
There are many different options when it comes to light options for microgreens. Our top two recommendations for microgreen grow lights are Brillihood LED lights or hykolity LED lights.
When shopping for grow lights, look for ones that have 1700 to 2000 lumens and a color rating of 6500k. These grow lights and bulbs are relatively inexpensive but will provide you with the light needed to grow a bountiful crop of microgreens.
Growing microgreens provides you with nutrient dense fresh foods. Microgreens can be grown year round when you have the right supplies, including grow lights. Our recommendations on the best grow lights for microgreens are based on research and trial and error.
