Growing Magnificent Microgreens

Small in size but big on flavor, learn how to grow microgreens for a year-round crop that’s perfectly at home in the kitchen.

Tray

For even more visual interest and variety in flavor, add some — or all — of these heirloom cultivars into your indoor microgreens rotation. All are available at www.RareSeeds.com. 'Molten Fire' amaranth; 'Scarlet' kale; 'Pink Summercicle' radish; 'Early Purple Vienna' kohlrabi; 'Zwolsche Krul' celery; 'Bull's Blood' beet; 'Red Rubin' basil; 'Smokey' fennel; 'Golden' purslane

Photo by Crystal Liepa

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Although some seed companies offer mixes designated as microgreens, there’s no such thing as specific seeds for microgreens. They aren’t grown using some special, almost magical seed that will produce a plant that’s only about 3 inches in height. Instead, microgreens can be grown from nearly any seed, representing one of the first stages of plant growth.

A plant enters the microgreen stage once the initial leaves, called cotyledons, give way to a plant’s true leaves. After becoming a microgreen, the growth into vegetable, herb, or fruit truly begins. In other words, if you plant seeds in order to get microgreens and then change your mind or leave them for longer than intended, the plant will begin maturing and, most likely, get too large for the pot you’ve chosen.

Fresh on the Scene

In terms of arrival on the home-garden scene, microgreens are the new kids on the block, but their popularity with chefs, small-scale farmers, and urban growers will likely propel microgreens past the trendy stage. Their cute size, mule-kick-level flavor, and nutritional clout make them a perfect addition to any indoor growing mix.

There’s a reason microgreens are catching on quickly. According to a recent study in the Journal of Agricultural and Food Chemistry, microgreens can have up to 40 times more nutrients than mature plants, ounce for ounce. Their nutritional density depends on the type of microgreen, but all seem lush with nutrients. Considering the nutrient boost microgreens can bring to a meal, keeping a small tray going in the kitchen is an easy way to benefit from their healthful qualities.

Most of all, though, there’s the flavor. A single, slender beet microgreen, only as long as a fingertip, can taste like a fully grown beet. Mustard and radish microgreens are far spicier than many people might expect, and carrot microgreens carry the fresh, sweet flavor of just-harvested vegetables. Also, when kept in glass containers in the refrigerator, microgreens can last for up to two weeks and still maintain their rich nutrient profile and hefty punch of flavor.

For those who are just getting started with indoor gardening, growing microgreens is an ideal initial project, and even for those who are experienced pros with kitchen gardens, the “crop” offers such endless variety that there’s always a new and zesty type of microgreen to try. So, let’s get growing.

Choosing Seeds for Microgreens

Although most seeds can grow into microgreens, some choices make more sense than others. Melons and squash, for example, produce thick and chewy cotyledons that don’t taste particularly good. Daikon radish or purple kohlrabi, though, are both exceptionally flavorful and provide pretty micros. Here are some guidelines for choosing the best plants for your indoor garden:

Personal taste: Those fond of strong, spicy flavors should gravitate toward mustards, arugula, radishes, cress, and other zesty greens. If you prefer a milder taste, stick with options like chard, basil, cabbage, or carrots. Imagine the full flavor of a vegetable whittled down to a sliver, and that should determine your choice.

Germination time: Some micros mature rapidly, even within a few days, while others might putter along and take 10 days to a few weeks. Most people aren’t trying to time micros according to menu planning or farmers-market selling, so germination time isn’t especially important, unless you’re creating a seed mix. In that case, it’s usually a good idea to put fast-growing varieties with each other to prevent harvesting a tray of half-grown micros.

Color and appearance: Plenty of micros boast visual appeal, and planting a variety based on color can yield a tray that pops. Red-veined sorrel is gorgeous in appearance, while red and golden beets sport brightly colored stems that seem almost neon. For micros grown into the true-leaves stage, it’s fun to pick types with visual interest like garnet mustard, with its spray of red color against a green background, or mizuna, with its tiny, tree-like leaves.

Price: When choosing seed mixes or other varieties of microgreens, keep in mind that any seeds designated as being specifically for microgreens should be the same price as seeds that don’t have that trendy title.

Good Plants for Indoor Microgreens

Nearly any microgreens seed mix is well-suited for beginning growers, and it can be tough to limit an indoor garden to just a few. To get started, here are some of my favorites:

Arugula: Boasting purple stems, arugula is a nice addition to any mix that’s heavy on green colors, and the spicy flavor is distinctive.

‘Red Giant’ mustard: Any mustard cultivar is fun to throw into a micro blend because the flavors will really come through. ‘Red Giant’ provides an added bonus because the leaves have red veins throughout, making them visually appealing.

Beets: With vibrant stems, both red and golden beets are incredibly pretty as they’re growing. They take longer to mature — sometimes three weeks to nearly a month — so I tend to grow them separately rather than in a mix.

Cress: These can be very delicate and susceptible to mold if overwatered, but when cared for properly, they grow very quickly, sometimes within just a few days. They’re easy to plant intensively and have a fresh, peppery flavor.

Komatsuna: A Japanese spinach with a strong mustard flavor, the microgreen version mimics the vegetable’s round, green leaves.

‘Ruby Red’ chard: With a mild, beet-like flavor, this cultivar also stands out for its reddish-pink stems, which look awfully pretty in a salad or sprinkled over eggs. Another great chard cultivar is ‘Bright Lights,’ which combines gold, pink, orange, red, white, and purple stems.

‘Red Russian’ kale: Personally, I love kale, so I tend to grow a lot of it during the year, both in micro and full-form versions. This cultivar has a nice pop of color thanks to a pinkish outline around the leaves.

‘Dark Opal’ basil: Herbs are always a nice addition to a micro blend, and I like a strong basil flavor. This cultivar also boasts a purple leaf, which is a refreshing contrast to the dominant greens seen in most micros.

Trays, Pots, and Other Containers

In addition to nutrient density, flavor, and the ability to impress dinner guests, microgreens are remarkably easy to grow in just about any type of pot or tray. Since they don’t grow to maturity, they possess shallow root systems that make them ideal for planting in a variety of containers.

An array of clever microgreen growing tactics exist, from putting a few seeds and a teaspoon of soil into bottlecaps, to utilizing old Pyrex baking dishes. But for an ideal system, I tend to prefer open-style seedling trays with drainage slots in the bottom. The slots keep the soil from collecting too much moisture, which can quickly lead to mold in a microgreen tray, even with adequate ventilation.

When choosing a pot or tray, keep soil usage in mind. Because of those roots, the micros don’t need the type of soil depth you’d see with plant starts or even indoor herb gardens. Save soil by choosing a smaller container, and make harvesting easier with a tray or pot that’s shallow rather than deep.

Soil Preparation

Microgreens do best in very loose soil with good drainage, so I tend to use compost mixed with a little vermiculite. The most important part of soil prep is to add some water to the mix before planting, which helps to hold in moisture during the germination phase.

When blending water and compost, go for a consistency that’s like a crumbly brownie mix — then pick up a handful and squeeze. If a few drops of water come out, that’s perfect. If there’s a steady stream of water, it means you’ve made the mixture too wet and should add more dry mix.

It’s not mandatory to premoisten the soil this way, and I’ve planted plenty of trays that did fine without it, but I’ve found that it can speed germination time by a few days if you use this method.

Planting and Care

Make sure you start with a clean tray, pot, or other container, and add just a few inches of your soil mix, making sure to fluff it up if necessary. Because the mix is moist, there’s often a temptation to push the soil down, but this creates a soil compaction issue that can turn your tray into a hardened brick when it’s put under light.

Here’s the tricky part: Seed generously. For those who are used to carefully dropping a single seed into a pot, it can take some time to overcome the psychological hurdle that microgreens present. But you need to seed heavily so that you can maximize your container’s space and harvest more efficiently.

Here’s an even more challenging part for many gardeners: Don’t cover the seeds with soil, vermiculite, or anything else. If you do, they tend to germinate unevenly, which isn’t important if you’re sowing seeds in a field, but is frustrating if your “field” is a small tray on your kitchen counter.

Water very lightly, and then place a dish towel or empty tray over your microgreens. This will help to keep the soil warm, and blocking the light for a few days will help the seeds to become healthier in general. You can peek inside if you want to see the magic — this isn’t a soufflé — but be sure to replace the cover if the seeds haven’t sprouted yet.

Once they show any sign of growth (about three to four days), remove the cover and water daily. Place under lights for at least six to eight hours per day.

Maintaining Growth

Once established, microgreens don’t require much care — that’s one of the major benefits of growing them. But there’s one important maintenance task that, if skipped, can put your micros in jeopardy: watering them properly.

When they’re just in the first stage of growth, before getting their true leaves, it’s fine to water from above, but once they’re looking very micro-like, it’s crucial to “bottom water” them so the delicate stems and leaves don’t get flattened.

Simply fill a kitchen sink, bathtub, or an empty tray with about an inch of water and set the micro tray into it for a few minutes. The plant will take up the water it needs and hydrate the roots that way. This tactic is also useful if micros are looking droopy and need to perk up.

Harvesting Microgreens

To harvest, grab a handful and cut. Really, it’s just that easy. In some cases, you’ll see seeds that haven’t germinated because others have blocked their light, so you can keep the tray going and see if you can get a second harvest from it. But in general, clear the tray and then start again.

Although many microgreens are sold in plastic containers — we sell them that way at farmers markets because it’s easier for transportation and cooling — the best way to keep them fresh is in glass containers. Pop them into a canning jar or another glass container with a lid, and they’ll keep for about two weeks, sometimes even longer, in your refrigerator.

The bad news is that long-term storage of microgreens isn’t possible or realistic, unless you throw them in a pasta sauce that gets frozen or canned. But with the very short time frame that comes with growing micros, keeping them long-term doesn’t feel as important as it would for some crops.

The last bit of advice I have for micros: Use them liberally. For many people (including myself), learning how to use microgreens can spark creativity in terms of cooking and flavor combinations. Put them over salmon, chicken, tofu, or pork. Top a pizza with zesty arugula micros, or sprinkle some kale micros on a sandwich.

Just when scrambled eggs seem like the most boring dish on the planet, I throw a handful of ‘Bright Lights’ chard micros on top, and — boom — I’m an amateur chef. Plus, who doesn’t love a tiny forest of plants that grows in just a few weeks? Microgreens have become an indispensible part of my food landscape, and if you start growing them, I suspect they’ll find a place on your plate as well.


This article was adapted with the permission of Cool Springs Press from Indoor Kitchen Gardening by Elizabeth Millard. Millard is a co-owner of Bossy Acres, an organic farm based in northern Minnesota.