Best Grow Light For Microgreens – The Definitive Guide

When you plan for your microgreen farm, lighting is one of the most important aspects to consider. Having the best grow light for microgreens can help you in every stage of the way. But some of you might have the question.

Do microgreens need light? Microgreens, after sprouting, need a healthy dose of light every day for the best results. Depending on whether you’re a hobbyist or a commercial farm, you can opt for either sunlight or grow lights. Both of them are fine but we would give the edge to grow lights as you have more control over it. Without sufficient light, microgreens can appear pale and weak.

Microgreens that get enough light during the growth period are superior in terms of the taste and nutrients. They are loaded with vitamins and minerals. If your microgreens are super green, you can be sure that they are loaded with a ton of nutrients. 

Types of Grow Lights

Sunlight

One of the best advantages of sunlight is that it is completely free.

If you’re a hobbyist or on a tight budget, then using sunlight for your microgreens is a solid idea. 

Do microgreens need sunlight? Yes. Your microgreens will need 4 to 8 hours of direct sunlight for the right amount of growth. You can place your microgreens of a Window sill that gets a lot of light or simply place them outside your house in a greenhouse-like arrangement.

One problem with using sunlight is that you’re not in control.

If you’re going to have a cloudy or a rainy day, there is no way to get your microgreens enough light. This may not be a big deal for hobbyists, but for commercial microgreen farms, this can be a big blow.

To combat this inconsistency with sunlight, we can opt for grow lights that will be under our control.

Incandescent Lights

tungsten lamp

Also known as halogen lamps and tungsten lamps, these are the ones with a thin filament inside. If you’re a young person, then there is a very good chance that you’ve not seen one.

Once current passes through the filament, it gets hot and produces yellow light. In terms of money, tungsten bulbs are the cheapest out there. But in terms of results, they are the worst-performing ones.

Incandescent lights produce more heat than light, that’s not a good thing for microgreens. Instead of enabling healthy growth, they can produce adverse effects.

These lamps are also not long-lasting. You may have to replace them once every 3 to 4 months, and that is not every ideal and would increase the cost of lighting over a longer time.

Fluorescent lights

These lights use current to excite the mercury vapor inside them. They produce ultraviolet light that is a bit different when compared to incandescent lamps.

Fluorescent lights are an improvement over the incandescent lamps. They have a much longer life and the best ones can last for about 20,000 hours. You also get better performance for the money. 

A lot of microgreen farmers use fluorescent lighting and prefer them over anything else. 

One hazard with fluorescent lights is that they let mercury out when they break. Mercury is toxic and can cause serious problems to both microgreens and humans. But the chances of the light breaking is one in a million so you don’t have to worry about that.

You can also go with CFLs as the advantages and drawbacks are pretty much the same.

LEDs

Light Emitting Diodes (LEDs) are a newer technology when compared to Fluorescent lights. These light use semiconductor leads that take in electricity and emit photons that result in light for your microgreens.

LEDs have a lot of advantages over the other lights. Some of them are listed below.

  • Efficiency is higher
  • Low power usage (Low wattage)
  • Lasts a lot longer than fluorescent lights (~45,000 hours)
  • More light and less heat
  • Free from mercury (non-toxic)
  • Despite the higher initial price, it is a solid investment
  • No electrical interference
  • Most durable lights in this list i.e. do not easily break when dropped
  • Lightweight and easy to mount

An LED light comes with different wavelengths as shown below

  • Far Red – Improves blooming and fruiting
  • Red & Blue – Helps in faster microgreen growth
  • Yellow – Inhibits faster growth
  • Blue & Violet – Heightens color, aroma, and taste
  • Green – Improves overall chlorophyll content on the microgreens
  • Ultraviolet – Growth rate reduces ending up damaging the plant

What Is An LED Grow Light?

Instead of going for a single LED light, you can combine multiple smaller LEDs to get an LED grow light. The main advantage of using one is that you can get a much wider wavelength which is perfect for microgreens.

Not a lot of people are seeing great results with LED grow lights. It makes us wonder if the switch from LED to a grow light is even necessary. 

The main reason for grow lights not working is the presence of too much red light. As we mentioned above, red light is perfect for improving the yield but it doesn’t work well in a microgreen’s case. What we need is a lot of blue light which will help in improving the color, taste, and aroma of your microgreens.

Can Any LED Light Be Used As A Grow Light?

Can Any LED Light Be Used As A Grow Light

Yes. You can use any LED light to grow your microgreens. Using regular LED lights over LED grow lights is often recommended by experts.

LED grow lights are used for microgreens because they can give you wide wavelengths. But the fact remains that you get a lot of red light in grow lights and they’re not that useful for microgreens.

When you use only grow lights for your microgreens, there is a good chance that you won’t get super green produce. Your microgreens will be yellowish but will still have a decent taste and nutrients profile.

This is because the absorption of chlorophyll is not great due to the lack of blue light. Blue light is usually found in the 430-490nm wavelength range. But in most cases, you will be fine with LED lights with a wavelength ranging from 400 to 700nm as they are perfect for plant growth.

What To Look For In LED Lights For Microgreens?

Tubular Diameter

Based on the tubular diameter, we have three common sizes that are popular among microgreen farmers namely T5, T8, and T12

The T5 LED lights have a diameter of 0.6″ which is the smallest of the bunch. The T8 lights come with a diameter of 1″ and the T12 lights come with a diameter of 1.5″.

The most common light used among these three is the T8 lights. In most cases, you will be fine with both T5 and T8 LED lights as they can give you better efficiency. T12 lights are not preferred as they come with an outdated ballast and also use more electricity.

Color Temperature

The color temperature of your LED lights is another important factor.

Color temperature is measured in Kelvin and most LED lights come with a color temperature between 2700K to 6500K.

For growing microgreens, you need an LED light that mimics the light from the sun. The effect can be achieved at a color temperature of 6500K so pick an LED that has this color temperature.

LED lights with a lower color temperature around 2700K are perfect for plants that are in the flowering and fruiting stages. For microgreens, these lights are useless.

Our suggestion is to go with a T5 or a T8 LED light that has a color temperature of 6500K and you should see the best results from your microgreen farm.

Wavelength

Having the right wavelength lights can help greatly when it comes to photosynthesis.

For microgreens, it is better to have LED lights that have a wavelength range from 400nm to 700nm. 

700nm is the far red side of the spectrum and is great for the flowering and fruiting stages of a plant. Unfortunately, these stages are not relevant when in the microgreen world. They can also inhibit growth.

Near 400nm, you get blue light which is fantastic for chlorophyll absorption and growth. This is very important for microgreens so lights ranging between a wavelength of 400 to 500nm will do a pretty good job.

If you get the LED light with a color temperature of 6500K, then you don’t have to worry about the wavelength.

How Many Lumens Do Microgreens Need?

Lumens are the measure of light brightness to the naked human eye. The best LED lights for microgreens will have a lumen rating between 1700lm and 2000lm.

Do note that lumens do not directly affect the growth level of your microgreens. They are just a measure for us, human beings, and is not a factor to judge the growth of your microgreens. 

So the next time you ask how much light do microgreens need, be aware that it is more of the vanity metric and you should be more focused on the color temperature and wavelength of your LED light.

When Should I Expose Microgreens To Light?

Before we answer this question, we would like to answer another question.

Do microgreens need light to germinate? No. We usually cover the tray so that you protect the moisture in the soil. You can cover your tray using another one, or you can use your method.

Leaving your tray open can remove the moisture in your soil and this could delay the germination process.

We open the microgreens and expose them to light only after they have germinated. This germination time will be different for different microgreens. In most cases, this will be around 2 to 6 days. You can expose your microgreens to light when they are around 2 to 3cm in height.

Here are some data on when you should expose certain microgreens to light.

  • Arugula – 4 to 6 days
  • Broccoli – 4 to 5 days
  • Chia – 3 to 5 days
  • Sunflower – 2 to 3 days
  • Wheatgrass – 2 days
  • Cauliflower – 4 to 6 days
  • Kale – 3 to 5 days
  • Cilantro – 7 days
  • Beet – 6 to 8 days

As you can see, each microgreen has a different blackout period. Some types don’t need a blackout period like barley, adzuki beans, chickpea, purslane, and many others.

The germination time of your microgreens will also depend on other factors like temperature, moisture level, and seed quality.

A temperature around 70 fahrenheit is the best optimum temperature for quick germination. The soil also needs to have good moisture content on it to reduce the overall blackout time.

How Many Hours Of Light Does A Microgreen Need?

The purpose of artificial lighting is to give microgreens a controlled and consistent amount of light that gives us the maximum yield.

We also do this to mimic sunlight. So it is always better to set hours that match the amount of sunlight in your area. If you’re not sure, then it is fine to keep the lights on for about 8 to 12 hours depending on the types of microgreens.

You can keep the lights on for a longer time (~12 hours) in summer and for a shorter time (~8 hours) in winter.

Do keep in mind that your microgreens can also get tired. Don’t overwork them and give them enough rest to get the best out of that batch.

How Far Should Lights Be From Microgreens?

How Far Should Lights Be From Microgreens

After gathering data from many experts, we can say that the average distance that works best for microgreens is around 25cm. You can try reducing or increasing the distance between the microgreens and the lights, but 25cm gave the best results.

One more factor to look at is the width of the light and also the number of lights you use.

Let’s say you’re using a T5 light for growing microgreens and placing it in the middle. At the time of harvest, you will find that the greens in the middle will show more growth, and the ones at the ends will have shunted growth.

To prevent this, it is better to go for a two-light setup where you use 2 fluorescent or LED lights for a more even spread of light on your microgreens.

Wrapping Up

We hope you were able to learn something about the lightings for microgreens. 

In simple terms, here’s how your grow light should look like. It should

  • be a T5 or a T8 light (Fluorescent or LED)
  • have a color temperature of 6500K
  • have a wavelength in the range of 300 to 700
  • have a Lumen rating between 1700 and 2000

If you don’t want to complicate it, you will be fine with a T8 light that has a color temperature around 6500K. All other factors will fall in line once you get this grow light for your microgreens.

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