Gardening will always be mostly about outdoor activity, but if you make good plant choices and cultivate the right indoor environment, you can grow practically any produce you want. Author and gardener Elizabeth Millard offers advice on how to grow fruits, veggies and more, year-round, in Indoor Kitchen Gardening (Cool Springs Press, 2014). The following excerpt on how to grow, harvest and preserve microgreens will have you adding fresh, vibrant flavor to meals throughout the seasons.
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Although some seed companies offer mixes designated as microgreens, there’s no such thing as a “microgreen seed.” They aren’t grown using some special, almost magical seed that will grow a plant that’s only about three inches in height. Instead, microgreens can be grown from nearly any seed, since they represent the first stage of growth of a plant.
These initial leaves, called cotyledons, of a seedling give way eventually to a plant’s “true leaves,” and from there the growth truly begins into vegetable, herb, or fruit. 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.
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 forty 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 how easy it would be to slip some micros into a kid’s meal for an extra nutrient boost, keeping a small tray going in a kitchen garden makes sense.
Most of all, though, there’s the flavor. A single, slender beet microgreen only as long as a fingertip, for example, 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, micros can last for up to two weeks, and still maintain their punch.
For those who are just getting started with indoor growing, microgreens are 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 something new and zesty to try. So, let’s get growing.
Choosing Microgreen Seeds
Although most seeds can grow into microgreens, there are some choices that make more sense than others. Melons or squash, for example, produce thick and chewy cotyledons that don’t taste particularly tempting. Daikon radish or purple kohlrabi, though, are both particularly flavorful and provide pretty micros. Here are some guidelines for choosing well:
Personal taste: Those fond of strong, spicy flavors should gravitate to mustards, arugula, radishes, cress, and other zesty greens. If a milder taste is preferred, stick with options like chard, basil, cabbage, or carrot. 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 ten 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, almost cartoonish, in appearance, while red and golden beets sport brightly colored stems that seem almost like neon. For micros grown into the true leaves stage, it’s fun to pick varieties with visual interest like garnet mustard, with a spray of red color against a green background, or mizuna, with its tiny, tree-like leaves.
Price: When choosing seed mixes or other microgreen varieties, keep in mind that anything designated as “microgreen seed” should be the same price as seeds that don’t have that trendy title.
Good Varieties for Indoor Growing
Nearly any microgreen seed variety is well geared 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 variety of mustard is fun to throw into a micro blend because the flavors will really come through; with the Red Giant, the leaves have red veins throughout, making them visually appealing.
Beets: So pretty as they’re growing, with vibrant stems depending on whether you’ve planted red or golden beets. They take longer to mature, sometimes 3 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 variety also stands out for its reddish-pink stems, which look awfully pretty in a salad or sprinkled over eggs. Another great chard option 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 variety 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 variety 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 boast shallow root systems that make them ideal for planting in an array 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 harvest easier with a tray or pot that’s shallow rather than deeper.
Microgreens do best with 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 you 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 also 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 the top of the micro tray. This will help to keep the soil warm, and blocking the light for a few days helps 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.
Once they’ve 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.
The task is 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, even another 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.
If you don’t have a way to bottom water, then just water carefully at root level, or mist heavily instead of watering.
Harvesting and Preservation
Getting Ready to Pick
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—at Bossy Acres, 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 in a Mason jar or a Pyrex container with a lid, and they’ll keep for a few 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 timeframe 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), 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 within just a few weeks? Microgreens have become an indispensible part of my food landscape, and once you start growing them, I suspect they’ll find a place on many of your plates, too.
Reprinted with permission from Indoor Kitchen Gardening: Turn Your Home Into a Year-Round Vegetable Garden by Elizabeth Millard and published by Cool Springs Press, 2014. Purchase this book from our store: Indoor Kitchen Gardening.