The very best light for growing microgreens, or any plants for that matter, is natural daylight from the sun – white, full-spectrum light. Many varieties of microgreens will grow indoors just fine using only the direct light (or even indirect for some varieties) that comes through your window. However, if you do not have a well-lit window, or maybe it’s winter and you are at a high latitude that only gets 8 hours or so of low-angle light, or perhaps you are growing your microgreens in a basement or closet, then you are going to have to supplement with artificial lighting.
First, a little education.
For many years, there have been three basic types of light bulbs available – incandescent, fluorescent and LED (light emitting diode.) Recently, incandescent bulbs have been legislated out of use in many areas, which is just fine for our purposes since they create too much heat (up to 90% of the energy they use) to be useful for growing plants. Fluorescent lights have been the go-to choice for most indoor growers due to higher availability, but in recent years LEDs have been the up and coming darlings as their availability has gone up and their prices gone down.
Light bulbs have three primary variables that you want to be familiar with when selecting them as grow lights. These are Kelvin, lumens and watts.
Kelvin is scientifically used as a scale for temperature, but when used in the context of lighting, it is a measurement of color. For simplicity, the higher the Kelvin rating, the whiter the light will be. A value of between 4500 and 6500 is going to be the closest to simulating natural daylight.
Lumens are a measurement of brightness. The higher the lumens, the brighter the light. For growing microgreens, a lumen value of at least 2000 is desirable. The lights I use for growing microgreens in my own home are 4000 lumens.
Watts are a measurement of the amount of electricity used to operate the light. This is what is going to affect the cost of running your grow lights. The plants only care about the Kelvin and lumens, so those are the primary factors to look for. But depending on the cost of electricity where you live, your wallet may care about the watts.
What about those fancy Red/Blue grow lights?
Light requirements for seedlings differs from that of flowering or fruiting plants. Growers that are growing plants indoors all the way to maturity use the different colors on the light spectrum in order to promote either vegetation growth (in the early stages) or flower and fruit development (closer to harvest.) Microgreens are harvested when they are still seedlings (baby plants.) White light that mimics daylight is all you need.
Your lighting solution needs to fit your growing space.
A four-foot shop light is probably not going to work if you are growing microgreens on your kitchen countertop. Conversely, a single-bulb clamp light equipped with a compact fluorescent bulb (sometimes called CFLs – the ones that look like an ice cream cone) will be great for a small table or countertop setup, but be insufficient to illuminate a four-foot long shelf
When calculating costs, you need to consider the cost of fixtures, bulbs and electricity. For many years, the common belief was that LED lights, being more energy efficient, were going to save more money on electricity, but were going to incur a higher cost to purchase. However, in recent times, this has changed. I was able to find a four-foot LED shop light at my local hardware store for under $20 that doesn’t even use bulbs – the LEDs are built right in! At only 4000 Kelvin, it’s not quite as white as I would prefer, but it’s super bright (4000 lumens) and only uses 40 watts. I can run it for 16 hours a day for only $1.07 per month!
However, don’t go buy a new light if you don’t have to. If you already have a shop light that uses fluorescent bulbs, (and you have the bulbs) use that. There are LED bulbs available that fit into those older fluorescent fixtures, so over time you can switch to those more energy efficient options as your fluorescent bulbs get burnt out (or broken.)
One other cost that is highly recommended is a timer that you can plug your grow light(s) into that automatically turns the lights on and off according to the schedule you set. It’s not the end of the world if you’re an hour late turning your lights on one morning, but for me, not having to worry about that part is a great convenience.
The best grow lights for microgreens are the ones you have available to you (even if it is one of those fancy Blue ones.)
Grow lights for microgreens are not complicated. You don’t need to use any special colors.
4500-6500 Kelvin. At least 2000 lumens. That’s all there is to it.
In summary, microgreens need a large enough light fixture (or a combination of smaller ones) to cover the space in which they’re growing. Fluorescent (including the “ice cream” CFLs) or LED lights will both work, although there may be cost differences. The most important thing is to get growing. Don’t let yourself be held up by waiting for the acquisition of the “perfect” grow light setup. Work with what you have available to you and make improvements if you need to as you go along.
***Do you have any experience with grow lights? Please let me know in the comments section below what you have tried, and what has or hasn’t worked for you.***
P.S. I want to give a special thank you to CaliKim, whose YouTube video about grow lights for starting vegetable seedlings really helped me out when I was first getting started with microgreens. She has some great ideas for inexpensive solutions and setups for home growers. I’ve included the video below.