Are LED Grow Lights Better than LED Shop Lights for Microgreens?

Obviously microgreens placed under a light source grow more vigorous than without light.

Also, for an environmentally conscious home owner using LED lights are a no brainer. Especially when growing non-fruiting short-term vegetative crops like microgreens.

However, is it necessary to use LED grow lights instead of say less expensive (per area lit) LED shop lights?

Will the growth, production, and plant vigor be much different using LED grow lights instead of LED shop lights?

We set up a test and the results are presented below.

LED Grow Light vs. LED Shop Light

Let's take a look at the lights we tested to answer the question stated above.

Remember, we aren't comparing commercial lighting systems here, this is for the home microgreen grower.

This is the first of a two-part LED light comparison series. You can read the second article by clicking this link. In fact, there may be up to four articles on this subject. You can sign-up to receive updates using the form below.

LED Grow Light

First the LED grow light is from Amconsure (click any photo to see a larger version when on a computer). A future post will explain grow lights in more detail.

There are a few reasons this grow light was purchased.

• The Amconsure LED grow light had a 3-way built-in timer. Although two of the settings are basically useless for microgreens, and the third, a 12-hour setting, works great. Twelve hours is long enough to provide good microgreen growth. Plus, I didn't want to buy another timer.
• The clamp is very handy to attach the lamp to many different table or countertop configurations and still position the lights over trays of microgreens. In fact, I found the clamp worked much better than expected.

• The three-head lights have 360-degree flexible gooseneck arms that provide many lighting and microgreen tray position configurations.

• The reported wattage is as high as the other reasonably price LED grow lights. However, I assume that the 30-watts is an equivalent measure of power. Most LED bulbs and lights are reported in watt equivalent values to make it easier for people to compare to non-LED bulbs.
• A reviewer reported that the lamp used only 13 watts. Watts is power, and is really a measure of electricity used and doesn't have much to do with the light output. However, it can be used relatively when comparing lights to each other.
• Lastly, for the all the options this LED grow light contains the price is reasonable. The light has other options not mentioned, but none of them are important for microgreen growth. 

LED Shop Light

These shop lights are nothing special, they just fit the bill at the time for size, price, and availability. However, I've grown microgreens and other plants under them successfully for over a year now.

Here's the new LED light I use. Instead of using two lights to light up a shelve, one of the new lights does the job! The light also comes with hangers that connect to the shelve with zip ties. The light is sold at Home Depot for only around $15.

Light Placement

LED Shop Lights

The two bars of LED shop lights are mounted under a plastic 5-shelf storage rack in a corner of my living room. The shelf can receive some sunlight from a bank of southeast facing windows. However, Syracuse receives few hours of sunlight in late December.

Amconsure LED Grow Lights

The LED grow lights are mounted on a stainless steel kitchen table using the attached clamp. The kitchen has no windows and receives no natural sunlight. There's a fluorescent light fixture and LED overhead light in the kitchen as well. These lights are only on when food is prepared, so about an hour or two a day.

The reason for placing the LED grow light in such a naturally dark room is to test if the LED light can grow microgreens in such conditions. Many home owners and apartment dwellers may not have a sunny place available to grow microgreens. If the light works it's an inexpensive solution for that problem.

Location & Light Differences

This test is far from scientific. That said, comparing grow rates, leaf development, and total mass of microgreen growth between the two light systems still should make some conclusive results.

Such as, are inexpensive grow lights worth the small investment; and, can microgreens be grown in a naturally dark room with Amconsure LED grow lights? The LED shop lights have produced trays and trays of microgreens, I know they work.

But maybe the LED grow lights are that much better. 

However, there are some differences in locations and lighting.

• The LED shop lights combined are equivalent to 50-watts, while the grow lights are 35-watts equivalent. 
• The microgreens under the shop lights will receive more natural light.
• The room where the shop lights are located is generally warmer than the kitchen.
• The LED grow lights have more reflective surfaces, the wall next to them is white and the table is stainless steel; while the microgreens under the shop lights are grown in a black plant tray with 2 1/2-inch sides.
• Both sets of microgreens are seeded with the same mass of seeds and will receive the same amount of water, the covers will be removed at the same stage of growth, and they'll be lit for 12-hours.

Expectations

At the start, I expect the microgreens under the shop lights will germinate and grow quicker because of the warmer temperatures and more natural light.

However, I expect the microgreens under the grow lights to be less leggy and more compact.

Because of the microgreen varieties grown (see below) I expect the shop lights to produce more mass.

What Microgreens Were Tested?

For this part of the experiment, I choose two reddish leaf microgreens, Red Acre Cabbage and Bull's Blood Beets.

The reason for the reddish leaves is to see how well they do under the red and blue grow lights. 

Grow lights use light wavelengths in the red and blue spectrum, hence the purple color, because most plants are green, meaning they reflect instead of absorbing and using green light for photosynthesis.

Curiosity made me wonder if the reddish cabbage and beets would grow well under the red lights. I will also test green leaf microgreens under both lights and post the results in another article. 

Equal amounts of each seed is spread evenly on 40 square-inches of a professional potting mix. The seeds are covered and kept in the dark until they germinate, then they're exposed to the light.

The microgreens are watered from the bottom. A timer on the shop lights is set a daily 12-hour period and the 12-hour daily setting is used on the LED grow lights.

Results: Let's Compare the Microgreen Growth

Let's compare the growth difference between the LED shop light and Amconsure LED grow light in a series of photos.

Day 6

Even though it's hard to tell, the growth on both the cabbage (left tray in both images) and beets is very even. 

Day 9 - Red Acre Cabbage Microgreens

The image above shows the Red Acre Cabbage trays on day 9. They are very equal in height, the LED shop light cabbage (the one on the left) is fuller and though you can't see it in the photo very well, the leaves are larger and a bit more shiny. 

Red Acre Cabbage Mass

A good way to compare how well the microgreens grow is to harvest them and weigh the mass of useable green. 

The LED shop lights produced 55.9 grams of cut microgreens. The LED grow light mass is 54.1 grams. 

The difference is about 3%, not much of a difference. Especially considering that the shop light microgreens were in a warmer room plus they had a bit of indirect natural light. 

Both lights grew Red Acre Cabbage microgreens well.

Below is a video showing the harvesting of the Red Acre Cabbage.

Continuing with Bull's Blood Beets - Day 12

With the beets, the growth is different. The shop lights produce a darker leaf and the plants grow shorter but wider. It's not that the germination is different, rather, the plants are more broad with larger leaves. 

The tray to the right, is grown under the LED grow light and the plants are much more leggy. I believe the redder leaves of the Bull's Blood Beets restrict the growth under the grow lights. 

Day 16

Day 16 is harvest day. Below are both trays of beets, those grown under LED shop lights to the left, and the Amconsure LED grow light on the right.

As you can see, the beets grown under the shop lights are uniform, dense, and have great color. The microgreen beets on the right are leggy, straggly, lighter green, and smaller leaf size.

The legginess of the LED grow lights surprised me. I expected them to be more compact. Maybe the light is not intense enough for the red-leaf microgreens? 

Bull's Blood Beet Microgreen Mass

As with the cabbage, both trays where harvested and the useable greens weighted. 

The beet microgreens grown under the LED shop lights weighed 29.9 grams. The beets grown under the LED grow light came in at 22.5 grams.

That is almost a 25% difference. Even though the shop light microgreens could've had better growing conditions than the grow lights. A production decrease of 25% is more than can be explained by indirect natural light and a few degrees more warmth.

What is Better for Microgreens, LED Shop Lights or Grow Lights?

It would appear that the LED shop lights are a better choice. At least for the varieties of microgreens grown in this experiment.

What's Next?

To see if the red-tinted leaves are a reason for the poor performance of the LED grow light, four more trays of microgreens will be sown. 

Two trays of a fast growing green microgreen like mustard or broccoli and a slower developing microgreen like basil. A tray of each will be placed under both types of lights and the growth will be compared. 

The above mentioned test was completed a couple of weeks later. The article can be read by clicking the link below.

LED Grow Lights for Microgreens, Do They Work?

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