Introduction

Microgreens and sprouts are not the same thing. Microgreens and baby greens are not the same thing. Sprouts, microgreens, and baby greens need different production methods. Each also has its food safety concerns. The Department of Health regulates sprout production. The Department of Agriculture regulates microgreens, baby greens, and most fresh produce. Today we’re going to discuss the main differences between sprouts and microgreens. We'll focus on the crop, the production method, and food safety.

Defining the Crops

Sprouts - As the name implies, the crop has only just sprouted before it’s consumed. What does sprouting mean? Sprouts are, as defined by Falcinelli and Galieni (2022), “[H]arvested when the cotyledons are still underdeveloped and true leaves have not begun to emerge, usually after 3–5 days from seed hydration. The entire plant (root, seed, and shoot) is consumed.” Think of the cotyledons as the leaves the plant is “born” with inside its seed; its “seed leaves.” The diagram below shows six basic developmental stages for a common garden bean. When eating sprouts, you’re likely eating a plant at the third or fourth stage. As Falcinelli and Galieni point out, the seed leaves are underdeveloped. The true leaves, labeled below as the foliage leaves, aren't apparent yet. Eating a sprout means eating the whole plant, from top to bottom. That includes the nascent root, seed, stem, and cotyledons. The image below shows what a bowl of bean sprouts looks like in real life. The long white projection are the beginning of the root structure.

Microgreens - Looking back at the diagram, microgreens would be the fifth or sixth developmental stage. The same 2022 paper defines microgreens as well. “While sprouts usually take less than a week to mature, microgreens are harvested for consumption within 10–20 days of seedling emergence. Microgreens, defined as tender, immature greens, are larger than sprouts, but smaller than baby vegetables or greens. They have a central stem with two fully developed, non-senescent cotyledon leaves and mostly one pair of small true leaves. The stem, cotyledons, and first true leaves are consumed.” If sprouts take 3-7 days to grow, microgreens take 7-28 days, depending on the variety. If we eat the whole plant when eating sprouts, we only eat the top half - stem and leaves - when eating microgreens.

Production Methods

Sprouts - Most seed varieties germinate when exposed to water. Most crops contain within their seed a limited supply of stored nutrients to fuel them through the early stages of development, before being photosynthetically active. Sprout production leverages this fact by simply wetting the seeds and letting them germinate as they would in nature. There is no soil or growth medium and little to no light. Why? Sprouts are harvested and packed after a few days of growth. So, they never reach their photosynthetically active stage. There’s no need to provide light. Similarly, sprouts are harvested before they can develop roots or draw nutrients from a substrate. So, there’s no need for soil or any other growing medium. In effect, sprout production is just a bunch of seeds tossed in a big jar with water. “Sprouts are commonly grown in the dark under high relative humidity.” (2022). There are nuances we don’t need to touch on, but those are the basics. Seeds, water, and a container.

If you visit the Sentrex website, you’ll see examples of commercial sprout production. Sprout production, depending on the equipment, requires lots of water and sterile, stainless steel equipment.

Microgreens - Farmers grow microgreens under similar conditions to most other produce. Expect a soil or substrate for rooting, a light source - natural or artificial, and good airflow. We already know that microgreens take many days or weeks longer to grow than sprouts. Microgreens will reach their photosynthetically active stage, which is why we need to provide a light source. Plants will die after a few days without a place to grow their roots. So, we must provide a suitable medium, like soil. Finally, we know mold thrives under conditions of high humidity and low airflow. That’s why you’re more likely to find mold in your bathroom, kitchen, or basement. We need to provide microgreens with good airflow to stave off mold development that would compromise plant growth and food safety.

Commercial microgreen growers either use greenhouses with modest climate control or fully indoor warehouses with complete climate control. If you visit the Farming Turtles Instagram, you can see an example of the former. Farming Turtles uses greenhouses with a combination of natural and artificial light, and natural and artificial airflow. If you visit the Piedmont Microgreens Instagram, you’ll see an example of the latter. We grow in a retrofitted industrial space with racks for vertical production, fans, dehumidifiers, and LED lighting.

Food Safety

The Department of Health (DOH) regulates sprout production. The Department of Agriculture (DOA) regulates microgreen production. Why? Sprouts are a higher-risk food than microgreens. So, their production is under greater scrutiny. Sprouts, as a food product, are older than microgreens. So, they've had more time to face issues, and thus regulation. Sprouts have developed a bad reputation for causing food-borne illnesses linked to E. coli and Salmonella. Why? Think back to how we grow sprouts. “Sprouts are commonly grown in the dark under high relative humidity.” (2022). Those conditions are perfect for breeding mold - dark, wet, and stagnant. Despite all modern safety precautions, sprouts still pose a higher risk than microgreens. Microgreens might someday fall under the DOH, but, for now, there are no microgreen-specific regulations.

In Summary

• Sprouts take 3-7 days to grow. Microgreens take 6-28 days to grow.
• You eat the whole sprout plant - root, seed, stem, and leaves. You only eat the stem and leaves of microgreens.
• Sprouts grow in high moisture, dark, and low airflow conditions. Sprouts are not rooted in anything, nor are they growing upright. Microgreens are rooted in a substrate or soil with access to light and good airflow.
• Sprouts pose a high risk to consumer food safety, and they are regulated by the Department of Health. Microgreens do not pose a high risk to consumer food safety, and they are regulated by the Department of Agriculture.

As a final word, sprout production only constitutes a handful of crop varieties. A nearly comprehensive list would include broccoli, alfalfa, clover, radish, mung, soy, wheat, and cilantro. However, nearly any annual food crop can be grown as a microgreen. We grow 30+ distinct varieties at Piedmont Microgreens from dill to sorrel to sunflower.

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