Microgreen Lighting Experiment: Fluorescent vs. LED Comparison

Disclaimer: This blog is for educational purposes only and is not intended as business or health advice. See the full disclaimer at the bottom of the post. This blog also contains Amazon Associate links. We may earn a small commission when you shop through these links at no extra cost to you.

Lighting is one of the biggest factors in indoor microgreens success, and it's also one of the most asked-about topics in our community. Back in 2020 we ran a side-by-side test with three different lighting setups on rainbow radish microgreens, documented every day, and recorded the full breakdown for our YouTube channel. That video is still one of our most-referenced lighting videos.

This blog walks through the original experiment, the harvest weights, the cost and ROI analysis, and what we've learned in the years since. If you want the full, current breakdown on lighting (with everything we've tested across the 7 years since this video), check our complete microgreen lighting guide, which is our updated cornerstone resource on the topic.

Brand new to microgreens? Pair this blog with our beginner's guide to growing microgreens for the full foundation.

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Quick Answer: Fluorescent vs. LED for Microgreens?

In our 2020 side-by-side test growing rainbow radish microgreens, all three lighting setups produced viable harvests, but the 300-watt equivalent LEDs delivered the highest yield (424 grams), followed by 18-watt LEDs (359 grams) and T5 high output fluorescents (358 grams). The 18-watt LEDs had the best ROI due to their low upfront cost. Since 2020, our preferred lights have been Barrina T5/T8 20-watt full-spectrum LEDs, which we've used and recommended for the years since. See our complete microgreen lighting guide for our current setup and recommendations.

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Experiment Setup

The experiment was designed to test how three different lighting conditions affected rainbow radish microgreens grown under otherwise identical conditions. Three setups were used:

• T5 HO Light (Top Shelf): T5 high output fluorescent lights.
• Light Blue Light (Middle Shelf): 18-watt LEDs, a weaker LED setup.
• Yellow Light (Bottom Shelf): 300-watt equivalent LEDs, the most powerful setup with the highest lumens and lux output.

For specific product recommendations on lights, racks, fans, and meters, we keep our current vetted picks in our Amazon affiliate storefront.

Before introducing the lights, each tray was seeded with 25 grams of Rambo Radish microgreen seed using coco coir as the grow medium. Coco coir is available through our Amazon affiliate link (we no longer sell coco coir directly), and quality microgreen seeds are available through our affiliate partner True Leaf Market.

All trays received the same germination process: 4 days stacked and rotated under 15 lbs of weight (per our Tray-Specific Seeding Guide PDF), then 1 day in blackout before being moved under the lights. Each shelf was documented over the grow cycle, with particular attention to growth uniformity, coloration, and taste. For more on the weight and blackout timing, see our weight to blackout transition guide.

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Observations and Results

Growth and Coloration

Day	Top Shelf (T5 HO Fluorescent)	Middle Shelf (18W LED)	Bottom Shelf (300W Equivalent LED)
7	No significant difference	No significant difference	No significant difference
8	Consistent growth	Consistent growth	Consistent growth
9	Comparable growth	Slight height advantage	Comparable growth
10	Uniform growth	Uniform growth	Most uniform, richest coloration

Harvest Weights

Shelf Description	Harvest Weight (grams)
Top Shelf (T5 HO Fluorescent)	358
Middle Shelf (18-Watt LED)	359
Bottom Shelf (300-Watt Equivalent LED)	424

Taste Test

Shelf Description	Taste Notes
Top Shelf (T5 HO Fluorescent)	Slightly spicier
Middle Shelf (18-Watt LED)	Comparable to bottom shelf
Bottom Shelf (300-Watt Equivalent LED)	Mild and clean

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Cost and Energy Analysis

One of the most useful parts of this experiment was looking past raw yield and into the total cost of running each setup, both upfront and ongoing. Keep in mind these 2020 numbers will not reflect current pricing, but the relative comparisons still hold up.

Cost Breakdown

Shelf Description	Light Cost	Total Grow Cost (Energy)
Top Shelf (T5 HO Fluorescent)	$88	$1.05
Middle Shelf (18-Watt LED)	$18	$0.55
Bottom Shelf (300W Equivalent LED)	$140	$1.15

Energy Usage

Based on running each light for 17 hours per day, which is the schedule we use under our current lighting setup:

Shelf Description	Power Draw (Watts)	Daily Energy Cost	Total Energy Cost (5-Day Grow)
Top Shelf (T5 HO Fluorescent)	107	$0.21/day	$1.05
Middle Shelf (18-Watt LED)	54.2	$0.11/day	$0.55
Bottom Shelf (300W Equivalent LED)	115	$0.23/day	$1.15

The 300-watt equivalent LED had the highest yield, but it also carried the highest upfront cost and the highest ongoing energy draw. Whether that's worth it depends entirely on what you're optimizing for.

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ROI Calculation

Assuming a simplified retail price of $1 per gram of microgreens (which is roughly in line with what restaurants and farmers market customers were paying in 2020, though pricing varies significantly by market and channel):

Lighting Setup	Initial Light Cost	Energy Cost per Cycle	Harvest Weight (g)	Revenue from Harvest	Total Cost	Profit per Cycle	ROI per Cycle (%)
T5 HO Fluorescent	$88	$1.05	358	$358	$89.05	$268.95	305.63
18-Watt LED	$18	$0.55	359	$359	$18.55	$340.45	1891.39
300W Equivalent LED	$140	$1.15	424	$424	$141.15	$282.85	202.04

ROI per cycle is calculated as profit per cycle divided by initial light cost, multiplied by 100. This table assumes the entire initial light cost is allocated to a single grow cycle, which is just for the comparison. In reality, the same lights run for many grow cycles (years even), so the actual lifetime ROI is much higher across the board.

A few clear takeaways:

• The T5 high output fluorescents performed well and offered a balance between yield and cost.
• The 18-watt LEDs delivered the highest ROI per cycle, mostly because the upfront cost was so low.
• The 300-watt equivalent LEDs gave the highest absolute yield, but the much higher initial cost dragged the ROI percentage down.

The "best" light really depends on your specific goals: maximum yield, lowest cost of entry, best long-term value, or some balance of all three.

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What We've Learned Since 2020 (and What We Use Now)

This experiment was a great snapshot of 2020 lighting options, but a lot has changed since then. LED technology has improved significantly, prices have dropped, and the lights we recommend today are different from what was on the market when we ran this test.

Here's the short version of what's changed:

• The 18-watt lights are now 20-watt. Since 2020, the 18-watt LEDs from the original experiment were updated by suppliers to 20-watt versions. We've been using and recommending the Barrina T5/T8 20-watt full-spectrum LEDs as our go-to lights for the years since this test.
• Fluorescents are being phased out. T5 high output fluorescents still work well, but LED technology has caught up and surpassed them on every metric: energy use, lifespan, heat output, and now even color spectrum quality. We rarely recommend fluorescents anymore for new builds.
• The current recommendation is full-spectrum LED at 5500K to 6500K color temperature. That's the sweet spot for indoor microgreens, and it's what we use in our grow space today.
• Light placement is just as important as light type. Hanging lights 8 to 12 inches above the canopy with a 16 to 17 hour daily light cycle is what gives us our most consistent results.

For the full breakdown of what we use today, including specific Barrina model recommendations and our complete lighting setup, see our complete microgreen lighting guide with 7 years of testing. That blog is the most current and most comprehensive resource we have on lighting, and it directly builds on what we learned in this 2020 experiment.

For our current vetted product picks on lights and rack accessories, the Amazon affiliate storefront is the best place to start.

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Conclusion

This 2020 experiment showed that all three lighting setups can produce a viable microgreens harvest, but yield, cost, and ROI vary significantly. The 300-watt equivalent LED gave the highest absolute yield. The 18-watt LED gave the best ROI. The T5 high output fluorescent landed in the middle on both metrics.

Since then, we've settled on Barrina T5/T8 20-watt full-spectrum LEDs as our preferred lights, and we've documented years of additional testing in our complete microgreen lighting guide. If you're setting up your first grow rack or upgrading existing lights, that's the resource we'd point you to first.

Want to go even deeper on indoor growing fundamentals? Check out our Beginner's Guide to Growing Microgreens PDF, our book Becoming a Microgreen Master, or our full Microgreen Masterclass course.

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Frequently Asked Questions

What's the best light for growing microgreens?

After 7 years of testing, our preferred lights are Barrina T5/T8 20-watt full-spectrum LEDs at 5500K to 6500K color temperature. They're affordable, energy-efficient, and produce excellent yields. See our complete microgreen lighting guide for our full current recommendations.

Do microgreens grow better under LED or fluorescent?

In our 2020 experiment, both performed well, but LED options either matched or exceeded the fluorescent T5 HO on yield. LED technology has improved significantly since then. Today, we recommend LED across the board: lower energy use, longer lifespan, less heat, and better color spectrum control.

How many hours of light do microgreens need?

We run our lights for 16 to 17 hours per day with 7 to 8 hours of dark. That's the schedule that has given us our most consistent yields and best color development.

How far should lights be from microgreens?

8 to 12 inches above the canopy is the sweet spot. Too close and you risk heat stress or color washout. Too far and you'll get leggy, stretched-out crops reaching for the light.

What color temperature is best for microgreens?

5500K to 6500K. This range mimics natural daylight and gives microgreens the spectrum they need for strong, even growth and good coloration.

Are expensive grow lights worth it for microgreens?

Not necessarily. In our experiment, the 18-watt LED setup at $18 had the best ROI by far, even though the 300-watt equivalent LED at $140 produced the highest yield. For most home and small-scale commercial growers, affordable LED options like the Barrina T5/T8 lights deliver excellent results without the premium price.

Can I use regular shop lights for microgreens?

Yes, especially modern full-spectrum LED shop lights in the 5500K to 6500K range. Many growers (including us) use shop-style LED strips for microgreens. The key is the color spectrum and intensity, not the marketing label.

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Related Blogs You Might Enjoy

• How to Grow Radish Microgreens: The Fastest Beginner Crop
• Complete Microgreen Lighting Guide: 7 Years of Testing
• How to Build a Professional Microgreen Grow Rack
• How to Start Growing Microgreens: Beginner's Guide
• How to Grow Broccoli Microgreens
• How to Grow Microgreens in 10x20 Trays
• Weight to Blackout Transition Guide
• Meet Our Reusable Silicone Grow Medium
• Why Are My Microgreens Moldy? Mold vs. Root Hairs
• Top Microgreen Growing Mistakes & How to Avoid Them
• Case Study: Coco Coir vs. Reusable Grow Medium

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Disclaimer

All information in this blog is based on our 2020 YouTube video "Microgreen Lighting: Fluorescent vs LEDs", available in our on-site Video Library. Costs and prices may vary due to changes in the cost of goods since the original 2020 experiment, as well as differences in brands and models of items used. Results may also vary depending on your specific grow space. This was a single experiment and is not meant to be a complete or final conclusion of all possible results. This blog is for educational purposes only and is not intended as health, environmental, or business advice. Always run your own experiments to confirm what works best in your space.

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Microgreen Lighting Experiment: Fluorescent vs. LED Comparison
Published: November 2023
Updated: May 25, 2026
All content is property of On The Grow®, LLC