Microgreens can be grown using any kind of seed and are thought to be nutrient dense.
For those of us living in northern climes, it’s easy to get an array of greens during the summer, but once those frosty, sub-zero days become constant, finding local greens turns into a treasure hunt. Fortunately, at our Minnesota farm, Bossy Acres, we always have a nutritious bounty in our kitchen—just on a much, much smaller scale.
For the past few years, we’ve concentrated our off-season efforts on microgreens, which look like sprouts but are grown in soil. The greens are the first stage of growth for a plant and can be grown from nearly any vegetable seed, including broccoli, cabbage, beets, kale, and even cress and mustard.
You don’t have to live in a northern climate to appreciate the appeal of these little wonders. Fairly simple to grow with seemingly endless variation, microgreens offer plenty of flavor in a small package and make a great addition to numerous dishes.
In terms of arrival on the home-garden and farming scene, microgreens are the new kids on the block. Although appearing more often on the menus at upscale restaurants, microgreens only reached star status in the last few years—even the word itself is fresh, says Mark Mathew Braunstein, author of Sprout Garden (Rev. ed., Book Publishing Company, 1999) and Radical Vegetarianism (Lantern Books, 2009). He notes that the first use of the term “microgreens” was in 1998.
There’s a reason microgreens are catching on quickly. Because they’re the earliest stage of a plant’s growth, many believe that they’re more nutritionally dense than their mature counterparts—a notion supported by a 2012 USDA study of nutrient and vitamin concentrations in 25 commercially available microgreen varieties. Microgreens also contain a surprising amount of flavor for such a small green. A single, slender beet microgreen only as long as a fingertip, for example, can taste like a fully grown beet. Mustard and radish microgreens have a spicy kick, and carrot microgreens carry the fresh, sweet flavor of just-harvested vegetables.
Photo by Rachael Brugger
Store microgreens in a glass jar in the refrigerator to preserve quality.
Microgreen Growing Materials
Because of their delicacy, microgreens grow best indoors or in a controlled greenhouse environment. Trying to grow them outdoors can produce inconsistent results and lost efforts, but it can be done. With that in mind, here’s what you’ll need to calibrate an indoor growing station.
Several companies sell microgreen seeds, including organic varieties, but in our experience, seeds labeled as microgreens don’t differ from those sold for regular planting. Beet microgreen seeds and beet seeds are identical—they’ll both grow beet microgreens.
One time to select microgreen-specific seeds is when you’re seeking blends. Some companies sell mixes that have an array of seeds in one bag, which can be more affordable than buying the seeds individually. In general, aim for budget-friendly options because seeds need to be planted far more densely than would be the case for full-sized crops.
After much experimentation, we’ve found that organic potting or germination mix works best for our microgreens. Commercial garden-soil varieties created too much compaction in our flats, especially because microgreens do best in pre-moistened soil. (More on that later.)
High-quality soil is particularly important with this type of indoor growing because microgreens’ shallow roots mean the same soil can be used for numerous rounds of growing and harvesting. As the soil’s nutrients begin to deplete, compost or other fertilizers, such as kelp, can be added in moderation. Be careful not to overload the soil with enrichments. We’ve found that, in addition to delaying growth in some cases, it tends to encourage excessive moisture retention, which leads to mold.
Containers or Flats
As long as there’s adequate drainage, microgreens can be grown in almost any container. In fact, after accidentally spilling some seeds in my car, I came back a few days later to discover mustard microgreens taking root in the carpeting. Obviously, this isn’t a recommended growing method (though it gives “fast food” a new meaning), but it does show that the greens can thrive with minimal care.
When growing in a space-constrained kitchen, you can opt for pint-sized containers that once held cherry tomatoes or raspberries because they have the small holes needed for air and drainage. I’ve even seen a children’s project in which microgreens are grown in plastic bottle caps. At our farm, though, we prefer standard-sized 1020 trays with holes, as they allow us to grow a large amount of microgreens at once.
How to Grow Microgreens
With all the components—seeds, soil and container—at the ready, it’s time to plant. Here are the basic steps for planting and growing microgreens:
Step 1: Moisten soil.
Wetting the soil before you add it to the flats creates a better starting environment for the seeds. Place the soil in a bucket or bin and add enough water to make the mixture moist but not muddy. (You should be able to squeeze a handful and have a few drops of water come out, but not a steady stream. The handful should also hold together loosely.)
Step 2: Set up containers.
Depending on how you want to handle drainage, you might consider doubling up on containers. In our greenhouse, we use single containers in flats over a layer of mesh so the extra moisture falls through to the ground. This setup doesn’t work well in a kitchen or other indoor area, so you’ll want to experiment to find a system that allows for drainage without wrecking your surfaces. Putting flats on slatted shelves worked for us. In a pinch, you can also use a cooling rack set over a baking sheet: It will allow for proper drainage, and you can periodically empty water from the cookie sheet.
Step 3: Fill containers completely.
Most microgreen roots won’t extend to the bottom of the flats unless the greens reach their second stage of growth or you’re using a shallow container. Regardless, microgreens are easiest to harvest when the soil is level with the top of the container.
Step 4: Spread seeds evenly and thickly.
Unlike seedlings that will be transplanted outdoors, microgreens don’t need ample space around each seed for establish strong growth. It’s best to give seeds a little room and not layer them on top of each other, but close planting maximizes your container space and allows for easier harvesting. Don’t put a layer of soil over the seeds, as this can inhibit growth.
Step 5: Spritz with water and cover.
Because the soil is already moistened, you won’t need much watering at this point, but a once-over with a fine mist is helpful. Cover the tray with a cloth, paper towel or raised plastic cover. We often use an empty soil bag because it won’t stick to the seeds and it enables us to repurpose the bag. Just be sure there’s some ventilation by either covering the tray loosely or punching a few holes in the bag.
Step 6: Lightly water daily as needed.
The cover will help retain moisture during the first couple days, so watering might not be necessary, but if soil looks dry, give it another fine misting. Be careful not to overwater, as this can lead to mold growth.
Step 7: Provide sunlight.
Remove the cover from your growing container when sprouts emerge and place near a light source. Microgreens don’t need a specific type of light, and many are fine placed near a window with filtered sunlight during the day. Avoid direct light at this stage, as the greens are delicate and can burn easily.
Step 8: Change watering system.
Once the microgreens start growing, watering from above, even with a light mist, can flatten young sprouts. It’s better to bottom-water them daily by placing the flat or container in a shallow pool or sink of water for about 1 minute, then removing it and letting it drain for a few minutes.
Step 9: Harvest.
Use scissors or a small harvest knife to cut microgreens as close to the soil as possible, being careful not to let any dirt into the mix. This method works better than yanking out the whole plant and rinsing it aggressively. If possible, eat within a few hours.
Step 10: Reuse soil.
To make the process more efficient, we often use the same soil repeatedly, adding nutrients with a handful of vermicompost from our worm bins. Occasionally, we also spray the soil with an organic kelp mixture. In general, though, with smaller-scale growing like you’d have in an indoor garden, the same soil can be used several times without adding anything.
Getting Quality Microgreens
Microgreens can be delicate, but they tend to grow quickly—usually within a week of planting—so it’s good to have a constant rotation going if you’re looking to have a steady supply of greens. Here are some tips for maximizing your seed bank.
Plant for space.
Although it’s fun to grow one variety in a container and experience the full taste of that microgreen, it saves space if you aim for a blend from the start. At Bossy Acres, we create combinations of seeds and then plant them together. For example, we mix beets, radishes, Red Russian kale and mustards together, planting them in the same flat so that we don’t have to harvest each separately and mix them together before taking them to farmers’ markets.
Use stray seeds.
No matter how carefully we package and label our seeds, some always go astray and gravitate to the bottom of the storage container. Rather than waste these seeds, we create a “surprise” tray blend to see what grows.
Create specific flavor blends.
After a few rounds of microgreens, you’ll likely have a pretty good idea of the flavors you prefer, whether it’s the freshness of celery or the zip of radish. You can use this knowledge to develop blends specific to your tastes. We sometimes plant a few varieties that go well together in dishes that combine their mature forms; for instance, we often have a “peas and carrots” blend.
Microgreen Storage Considerations
Although microgreens are sometimes sold at co-ops or farmers’ markets in plastic containers with holes for air circulation, we’ve found that any type of plastic-based storage container considerably shortens the shelf life of harvested greens. Even with air holes, the plastic tends to trap moisture. After only a few days, the greens in the middle of the container begin to get gummy and can begin to mold in a surprisingly short period of time.
Ideally, harvested microgreens should be stored in glass jars in the refrigerator. This method extends the life of greens, sometimes up to three weeks. Any exposure to humidity turns the delicate greens to mush fairly quickly, so your best bet is to use them immediately after harvest.
Using Microgreens in Recipes
Microgreens lend themselves to a range of dishes and are ideal as a garnish or flavor enhancement, similar to a condiment. We sprinkle them on salads, sandwiches, soups, eggs and any dish that needs a bit more kick. Radish microgreens on a tuna-salad sandwich and beet greens atop squash soup are among our favorite combos.
Microgreens’ strong flavors and nutritional density are a valuable addition to any gardening plan, especially in the early spring when the body starts craving fresh greens. As Braunstein notes, tending to microgreens will be a joy, not a chore. “Grow them knowing that you are being good to them,” he says, “and thank them knowing that they will be good for you.”
About the Author: Elizabeth Millard is a writer and co-owner of Bossy Acres, an organic farm near Minneapolis, Minn.