Microgreen Grow Lights Setup

Microgreens are an excellent crop for anyone to grow because they are very flexible with their requirements, including lighting. Because microgreens do well using a variety of light sources, it's easy for the home grower to start where they are and still produce delicious microgreens.

To grow microgreens, you can start with a few trays by a sunny southern window or invest in a full vertical rack system with high-powered LEDs and commercial production.

There are many factors to consider when recommending the right lights for your microgreens grow setup. Are you growing for home use or commercial sales? How many trays are you growing? Do you have access to sunlight, for example, a greenhouse or sunroom? Are you planning to grow year-round? Do you need reliable harvest times, or are you more flexible? How much money can you invest in your light system?

How Much Light Do Microgreens Need?

Two factors are involved in this question:

1. The quality and strength of the light source
2. The duration of lighting. Six hours of light is the minimum required to grow healthy microgreens, but more is better. The strength and quality of light will depend on your choice of lights. 

Here, we will review the most popular lighting options, ranked from lowest to highest cost, and list the pros and cons of each.

Microgreen Grow Light Options

Sunlight and Natural Light for Growing Microgreens

This is, of course, the cheapest and most complete spectrum light source available. For the home grower, any sunny windowsill or small greenhouse can be used to grow microgreens, though with windows you may encounter more curved stems and slower, leggier growth. Windows can provide enough light to get you by, but are really only an option for those growing at home for personal use.

In larger-scale operations, greenhouses or high tunnels with tables can be used to grow microgreens when limited space is not a concern. In a greenhouse or high tunnel, you don't need additional artificial lighting to grow microgreens well.

Pros: Free, readily available, no wiring or timers required, full-spectrum light in the 6,500 K range on a clear day.

Cons:

• Inconsistent due to seasons and weather
• Produces heat that can affect growth
• Does not work well in vertical rack systems
  Requires supplemental lighting in the winter months
• Can cause leggy microgreens and slow growth in some scenarios

Fluorescent Shop Lights

Fluorescent shop lights are similar to LEDs in light production, but use more power and produce more radiant heat, so we don’t recommend them here. They also often contain mercury, which can contaminate your grow area if the bulbs break. If you are using existing fixtures, we recommend replacing the Fluorescent and CFL bulbs with LED.

LED Bulb Shop Lights

LED bulb shop lights can be purchased at most big box stores for around $20 a piece, and they are a standard 4’ long. These make an excellent trial light when you are ready to try growing indoors or expand to a vertical rack and increase growing capacity in a limited footprint.

These LED shop lights work fine for microgreens that have shorter growing cycles, but struggle when trying to grow microgreens with longer growing cycles, like herbs. If you want to grow these kinds of microgreens, you should consider an alternative lighting system. We have a top ten list of our favorite microgreens to grow here that you can use as a jumping-off point.

Pros: Inexpensive, easy to find, acceptable in many light spectrums, produces minimal heat, can usually be daisy-chained 3-4 lights, and works with 120v household electrical outlets.

Cons:

• Bulbs are often unprotected from water and dust, making them susceptible to damage.
• Brands vary greatly in quality
• Designed to be installed horizontally only
• Less efficient than strip LEDs
• Generally last far fewer hours than strip lights
• Shop lights are offered in many spectrums not ideal for plant growth

LED Strip Grow Lights (T5)

Strip grow lights like the ones we sell here, designed for gardening and growing microgreens, are available in multiple sizes and intensities. They are often sold in the same standard 4’ as shop lights, but other lengths are available. Full-spectrum strip lights above 5,000k run from $75 on the low end through to $650.

Most grow lights offer a standard growing area of 4’x2’. They can come with or without the surrounding reflector that gives it the classic shop light shape, which helps redirect light and therefore increases efficiency. This maximizes the light available and can help increase microgreen yields.

These lights are commonly used in vertical growing systems because they can be installed vertically or horizontally.

Pros:

• Moderately expensive
• Can be found in hydroponic stores and online
• Full light spectrum 4,500k and above allows for longer growing periods
• Produces minimal heat
• Efficient watt to lumen ratio
• Good ones offer lighting surfaces that are protected from dust and water
• Can usually be daisy-chained up to 7 lights
• Most work with 120V household electrical outlets
• Some can be installed vertically if needed for your setup

Cons: Moderately expensive(pro or con depending on your situation); quality, efficiency, and longevity can vary greatly between brands.

LED Panel Lights for Growing Microgreens

These are top-of-the-line growing lights for indoor use and can be used for microgreens and other types of plants. They are generally used for large-scale commercial indoor plant growing that requires plants to reach full size or the flowering stage.

The high light intensity found in these lights could be considered overkill for growing microgreens. Ranging in price from $99 up to thousands of dollars, they can be very expensive for a small grower. The area these lights cover ranges from 3’x3’ for smaller panels to 8’x8’ for larger panels.

Pros: Available in a variety of sizes, intense full-spectrum light, variable sizes for customized growing spaces, and highly efficient watt-to-lumen ratio.

Cons:

• Expensive
• Thick profile limits their ability to work in vertical rack systems
• Generally requires separate ballasts for electricity
• Must be purchased from specialty suppliers online or in hydroponics stores if available in your area

How far should my lights be from microgreens?

The distance your lights need to be from your microgreens is generally 6 to 12 inches above your microgreens. However, the type of light source you use can affect the ideal distance, as some lights produce heat that can burn the microgreens if placed too close.

Most LED strip lights do not generate enough heat to cause problems and work well 6-12 inches from the surface of the growing greens. The farther the greens are from the light source, the more they will “stretch” and become leggy.

Panel lights are higher-intensity and can be placed farther from the growing surface without much light loss.

How Many Hours of Light Do Microgreens Need?

In general, plants (including microgreens) need at least 6 hours of quality light each day to grow. If you are using sunlight as your main light source, you cannot really control the light exposure or intensity. But by being aware of shade patterns and light direction when setting up your system, you can maximize the light available to you.

When growing indoors, it's important to experiment with the light sources available to you so that you can grow your microgreens effectively and easily in a way that works for you. Some growers keep lights on 24/7, others use a 12-hour on, 12-hour off modified daylight system to grow their microgreens.

You can also use an 18 hours on/6 hours off system, which provides a balance between pushing for growth and allowing "rest" time for the plants. Some growers say this system provides the best color and flavor in microgreens, so it's important to test different light exposure times until you find something you're happy with.

What do light spectrums have to do with growing microgreens?

Microgreens normally don't need as high a light spectrum as available to them to grow effectively. Light spectrum comes more into play when you're dealing with other types of plants that have longer growing cycles (tomatoes and peppers) or plants that you're trying to push to the flowering stage (chamomile, zinnias, cross-breeding experiments).

However, some types of microgreens do need a higher light spectrum because they take longer to grow. When growing herbs or other plants for micros with a growing cycle longer than 20 days, upgrade your lights to produce a color temperature above 4,500k.

Most lights will be labeled between 2,000K to 6,500k. On the lower end of this scale (color temperatures from 2,000K to 3,000K), “warm white” appears orange to yellow-white.

Color temperatures between 3,100K and 4,500K are referred to as “cool white.” This range will emit a neutral white light.

Above 4,500K, it emits a blue-white light that mimics daylight and is ideal for any plant with a growing cycle longer than 20 days, including microgreen herbs.

What are the best lights for microgreens?

When it comes to lights for growing microgreens, there are a few things to consider. The most important factors are the light's wattage, lumens, and spectrum. Other specs, such as coverage area and PAR levels, can also be important depending on your setup. There are many factors that go into determining which lights are right for you.

LED grow lights are a popular option because they are affordable, energy-efficient, and produce consistent results. They come in a variety of spectrums, so you can find one that matches your needs. Additionally, they are energy-efficient, which makes them environmentally friendly and help you save money on your electric bill.

How many watts do microgreens need?

Watts are not a good measure of light for grow lights, since watts are a measure of energy use, not light output. LED lights use far fewer watts than other types of bulbs. 

Microgreens thrive with supplemental light, but they don't need as much as other plants. This is because most microgreen varieties are grown in short cycles of less than 20 days. We provide flexible grow lights for microgreens and other plants.

What's a T8 fluorescent?

A T8 fluorescent light is a type of tubular light that is 8/8 of an inch in diameter (aka one inch) compared to a T5 light, which is 5/8" in diameter. A T8 is larger in diameter and longer than a T5. The lumens and watts of a T8 are typically lower than those of a T5 light, so while it is more energy-efficient, you end up unable to reach high enough lumens for most plants to grow.

A T8 fluorescent light would be sufficient for microgreens if you intend to grow them only with a growing cycle shorter than 20 days. If you grow a longer-cycle microgreen or want to use these lights for other plants as well, a T8 will not be the right light for you.

FAQs for Microgreen Lighting

When should I expose microgreens to light?

Microgreens should be grown in darkness (often stacked, as described in this article) for 3-5 days after sprouting to ensure higher yields and easier harvesting. Slower-growing microgreens will be on the longer end of this spectrum, while faster-growing microgreens will be on the shorter end.

How do you know your microgreens are getting enough light?

If your microgreens aren't getting enough light, they will stretch out, weaken, and thin. Leggy microgreens result from insufficient light. When they lack light, the plants stretch toward it. This makes them less aesthetically pleasing and affects the greens' flavor.

Too much light or light placed too close can harm microgreens. It can cause them to lose their color and stockiness and burn the tops.

How many hours a day should your microgreens get light?

Microgreens need at least 6 hours of light, but do best on an 18-hour-on, 6-hour-off schedule. Some growers prefer an even 12-on, 12-off model, but we prefer extending the light period to encourage faster growth.

What is the best color temperature for microgreens?

The best color temperature for microgreens is around 4,000 K to 6,500 K. This range provides plants with enough blue and red light for photosynthesis, resulting in fast growth. Daylight colors have a color temperature between 4,600K and 6,500K, so using fluorescent light bulbs in this range will be ideal.

Microgreens can be grown at lower light temperatures, but will have the best color and grow fastest in this optimal range.

What light intensity do you need for microgreens?

Microgreens need at least 20 watts per tray and ideally lumens in the daylight spectrum (4,600K-6,500 K). The amount of light you need for microgreens depends on the light intensity and how close it is to the plants. Our automated grow rack features 4 T5 LED lights at 6,500K per shelf.

Can a grow light be too strong?

Grow lights can be too strong if placed too close to the plants or designed for commercial operations and used at home. Some lights are so intense that they can bleach the colors of everything around them, making them not a good choice for a home grower.

The stronger the grow light, the further away from the top of the plants the lights should be. Use a T5 as a standard light source for all plants, including microgreens.