Fluorescent vs LEDs - The Impact of Lighting on Rambo Radish Microgreens Growth

(Disclaimer: this is not intended to be business or health advice, read the end of the blog for more info. This blog also contains some Amazon Associate links that we make a small % of when you shop through the links with no extra cost to you.)

Introduction

Gardening enthusiasts and microgreen cultivators are often on the lookout for ways to optimize plant growth and yield. One of the critical factors influencing the growth of plants grown indoors, especially microgreens, is the type of lighting used. In this blog post, we delve into an experimental comparison that we conducted in 2020 of different lighting setups on the growth of rainbow radish microgreens. The experiment spanned over several days, with daily updates and observations leading to some insightful conclusions. You can watch the full video above:

Experiment Setup

The experiment was designed to test the effects of different lighting conditions on rainbow radish microgreens. Three different lighting setups were used:

• T5 HO Light (Top Shelf): T5 high output lights. - Fluorescent Lighting
• Light Blue Light (Middle Shelf): 18 Watt LEDs - A weaker LED setup.
• Yellow Light (Bottom Shelf): 300 Watt Equivalent LEDs - Representing the most powerful LEDs with the highest lumens and lux output. 

Before introducing to the lights and starting the experiment, each tray was seeded with 25grams of Rambo Radish Microgreen seed, using Coco Coir as the grow medium. They received the same germination times of being stacked & rotated over 4 days under 15lbs of weight, then switched into 1 day blackout before introducing to the lights. Each shelf's growth was documented over a period, with particular attention to the Microgreens growth uniformity, coloration, and taste.

Observations and Results

Growth and Coloration

Harvest Weights

Taste Test

Cost and Energy Analysis

Cost Analysis

Energy Usage

Assuming the lights are operated for 17 hours a day:

Despite the higher upfront cost and energy usage, the bottom shelf's yield and quality seemed to justify the investment.

ROI Calculation

Assuming a simplified market price of $1 per gram of microgreens:

The ROI per cycle (%) is calculated based on the profit per cycle divided by the initial light cost, multiplied by 100. This table assumes that the entire initial cost of the light is considered for a single grow cycle. The actual ROI would increase over time as the lights continue to be used for subsequent grow cycles.

While the T5 High Output fluorescent lights performed well, offering a balance between yield and cost, the 18 Watt LEDs emerge as the most cost-effective option, offering the highest ROI per cycle. The 300 Watt Equivalent LEDs, while providing the highest yield, have a significant ROI due to the higher initial cost of the lights. The "best" light depends on the specific goals and constraints of the grower.

Conclusion

This experiment sheds light on the importance of choosing the right lighting for microgreens cultivation when growing indoors. It highlights that while upfront costs and energy usage may be higher for certain lights, the return on investment in terms of yield and quality can be significant.

Note on Lighting Changes Since 2020

Since 2020, the 18-watt lights used in the experiment have been switched by the suppliers online to 20-watt lights, which is primarily what we use and have used since. This change would affect the energy consumption and cost analysis if the experiment were to be repeated.

Disclaimer

*All information found within this blog is based off of our 2020 YouTube video “Microgreen Lighting: Fluorescent vs LED's - On The Grow”. Please note that the mentioned costs and prices may vary due to changes in the cost of goods since the creation of this video, as well as differences in the brands of items used, and results (depending on your grow-space). This was a single experiment and is not meant to be a complete conclusion of potential results. This is also not intended to be used as health, environmental or business advice. Always do your own experiments too. *