What are the best type of grow lights for microgreens? Are all grow lights created equal? The short answer to the second question is a definite, no.
In fact, some lights won’t even work for vegetable production indoors. If you choose the wrong light, your microgreens or other seedlings will become leggy (too long in the stem) and pale.
If you’re a new grower or looking to improve your skills in growing, the plethora of options for lights when you have microgreens may leave you feeling overwhelmed, confused, or have you picking one and hoping for the best.
But we’re here to make a simple guide for you based on plant science and proven methods that work.
Now you’re asking, what type of lights do I need for microgreens? A good grow light must be full-spectrum, 6400K (bright), and many LED lights available are not.
Let’s look more closely at why this matters and how much light microgreens indoors truly need.
Plants Respond to the Right Kind of Light
With so many advantages to LED (Light Emitting Diode) lighting, most growers are opting to use these instead of fluorescent grow lights or other options. And we completely agree, LED lights are great. They produce less heat, have a longer lifespan, and are much more energy efficient.
However, not all LEDs provide the same wavelengths.
An article by plant biologist Dr. E.R. Meyer explains in detail how plant growth is affected by limiting factors. A limiting factor is anything that could mean your plants don’t get enough of any one factor they need that affects their growth.
Plant growth is determined by limiting factors, if your plants do not receive enough of
any one (1) factor they won’t grow at the maximum rate no matter how much of any other factor
you give your plants. — Dr. E.R. Meyer, plant biologist
Plants are sensitive to light. They need certain color spectrums to grow. The light spectrum is comprised of various colors, each with its specific wavelength. The primary colors of interest for microgreens are red and blue because these colors provide the most benefit to the plants.
Many of the lights often purchased and used for microgreens, though, are lacking enough blue light. They tend to be higher in yellow wavelengths, which doesn’t support the growth of the plant enough. So the end result is a leggy, thin, and overall weaker microgreen.
Red light is also an important part of the growth process. Both red and blue light are easily absorbed by plant chlorophyll pigments. As noted by Dr. Meyer in the same article quoted above, red and blue light are the most important when it comes to vigorous growth.
Microgreens do benefit from other colors, but to a lesser extent. So focus on what matters most.
What are Lumens and Kelvins?
If you read the specifications on lights, you’ll see these words appear. What do they mean?
Lumens indicate the amount of visible light emitted by a light source.
Kelvin (K) is color temperature. It represents the perceived warmth or coolness of the light (think what kind of tinge or glow it gives off overall).
What Kind of Light is Best for my Seedlings?
Like we mentioned, we need to choose a good light for our microgreens or we’ll get nowhere when it comes to growing.
The problem is that there are plenty of LED light outputs designed for simply lighting a room and not growing purposes. So it’s important that you purchase a full-spectrum, 6400K (5,000+ lumens) for optimum growth.
Remember that the overall look of the bulbs should be a bright white, not yellow or pink-tinged. This mimics natural sunlight as much as possible.
How Close to the Light Should Microgreens Be?
This is a common question. We recommend a distance of approximately 12-14 inches from the top of the microgreens to the lights. This allows for optimal light penetration without causing excessive heat or light stress on the plants.
How Many Hours of Light Should Microgreens Have?
You’ll get various opinions on this, but our recommendation is 12 hours of light and 12 hours of darkness. Plants need time to rest and prepare new growth in the dark. This split of half light and half dark has worked extremely well in our operation.
Benefits of LED Grow Lights
When it comes to cultivating plants, including microgreens, LED grow lights offer numerous benefits compared to other options. One key advantage is the ability to produce a full-spectrum of light, closely mimicking the natural sunlight that plants require for optimal growth.
Full-spectrum LED grow lights comprise a blend of various color wavelengths, catering to the specific needs of plants during their different growth stages. In this case, we want to have the best type of light for microgreens (seedlings).
You’ll also notice energy efficiency. LED lights consume significantly less power compared to other light sources, while still providing the necessary intensity for plant growth. They have relatively lower heat output, especially compared to fluorescent bulbs. This will reduce the need for cooling systems and save you more money.
One of my favorite things about LEDs is their long lifespan. LED lights can last up to 50,000 hours, significantly longer than a fluorescent (which is only 20,000 max and takes more energy).
LED vs Fluorescent
When comparing LED grow lights with fluorescent lights, we notice several advantages in favor of LEDs. Firstly, LED lights are more energy-efficient, using up to 50% less energy than fluorescent lights, which translates to lower electricity costs.
Secondly, LEDs have a longer lifespan and require less maintenance, making them a more convenient and cost-effective option for microgreen growers. They emit less heat, reducing the risk of overheating and potential plant damage.
LED vs HID
Some growers have chosen High-Intensity Discharge (HID) lights, such as Metal Halide (MH) and High-Pressure Sodium (HPS) lamps. However, LED grow lights offer several advantages over HID lights for microgreen cultivation. LED lights have a much lower energy consumption, running at 40-60% less energy than HID lights.
As with fluorescents, they also generate less heat, reducing the risk of overheating and the need for additional cooling equipment. LEDs have a longer lifespan, reducing replacement and maintenance costs.
Power & Cost Considerations
We know that LED grow lights consume fewer watts per unit of light produced, leading to lower electricity bills.
Initial costs might be higher than traditional lighting options. You may not want to put out the money on LEDs to start with, but given their longer lifespan and lower power consumption, LEDs often pay for themselves in a relatively short timeframe.
When we used fluorescent grow lights, we had to replace them often. This quickly became expensive and we’ve spent less over time by making the switch.
But the biggest reason to choose a high quality LED is to ensure that you get the best microgreens you can. The most important factors for microgreen success are light and temperature, good soil, and the right balance of water.
Where Can I Find a Good LED That’s Affordable?
You might be tempted to buy an LED grow light off Amazon because they’re inexpensive and claim to be good. But you may be disappointed in the results like we were. Just because they say “grow lights” doesn’t always mean they really are.
The quality of the light is key to your success. It’s best to choose a company with a good reputation for selling good growing products.
Remember, you need 5,000 lumens or more plus a temperature (K) of 6500.
These LED strip grow lights from Bootstrap Farmer are a good option and we have some of these in our operation. The downside is they’re somewhat costly. Even though they’re worth the money, you may not be able to fit that into your budget.
A more affordable option that’s just as good is to buy from HTG Supply. We have been more than satisfied with the results from using their products and that’s our top recommendation for growers. Here are some to choose from:
LED 4’ T5 Grow Light (Full Spectrum) This fixture is a 2 bulb LED and easy to set up. It’s great for anyone just starting out or growing on a small scale.
If you start a business with microgreens and want to expand, you can use the same type of LED light with 4 bulbs for a larger shelf.
And for a really simple start, this strip light is similar to Bootstrap Farmer’s design but less money and only 3 feet long. Still, if you’re new and just want to try growing microgreens, you can opt for this strip LED grow light.
They’re efficient, bright, and well made.
Looking for an optimal light for lettuce starts? Try AgroMax Clone Pro 9000K strip lights.
What if I Want to Switch From Fluorescent Fixtures?
You don’t necessarily have to buy entirely new light fixtures if you’re currently growing under a fluorescent one. Our lights are made by HyrdoFarm and were wired for fluorescent bulbs.
We found a simple solution through a company called HTG Supply. There’s a retrofit full-spectrum LED T5 tube (6500K) made by AgroMax that replaces the old fluorescent tubes without needing to change any wiring.
Same fixture, different light bulbs. It couldn’t get any easier than that! Who doesn’t want to save time?
The contrast between the two lights was noticeable. The LEDs were brighter and much more white in appearance and reflection. Our microgreens are happy and so are we.
Soil, Water, Lights…Action!
By taking the time to create an environment where your microgreens can thrive, you’ll end up with a much better end result. Whether you’re growing for yourself or selling microgreens to others, the light you choose is one of the most important factors.
Our microgreens are more vibrant and healthy under these lights.
Don’t settle for less than optimal. Choose a 5,000 lumens, 6500K LED grow light and get growing.
Soil is also a critical component to success. Read this post to find out more.
About Bronte & Candy Austin
Bronte and Candy are a mother and daughter team who have been operating their organic farm, Girly Girl Greens, since 2017. They deliver microgreens on a weekly basis to the local community and chefs in Seattle and Bellevue. For them, growing success is all about healthy soil.
When they’re not writing posts or working with the crops, they like to enjoy the outdoors, spend time with family and friends, or relax with a cup of coffee and a good Hallmark movie.