I am interested in using more microgreens and would like some advice on how to grow them at home.
–Tim Appleton, Highland Park
Microgreens are the sprouted seeds of various edible vegetables and herbs grown in small, shallow containers. Routinely used by fine dining chefs, microgreens have intense flavors while adding visual appeal to dishes. They are also concentrated in nutrients, so they are good for you, too. They are difficult to find in stores and expensive to buy, but easy to grow year-round indoors.
Start by choosing a small, shallow container such as a seed flat, or repurpose a plastic takeout food container. You only need about an inch (2 inches maximum) of a well-drained growing medium designed for containers. The container you choose must have drainage holes in it. It is critical that the soil be kept moist throughout the process.
Moistening the growing medium before filling your containers is recommended. Using seed trays with water wells underneath is the perfect way to keep the medium consistently moist throughout the growing period. Otherwise, check your containers daily and mist when the soil begins to look dry.
Very small seeds like lettuce can be sprinkled on the surface of the growing medium, misted and covered with a clear plastic lid until they sprout. Larger seeds will need to be sown 1/4- to ?-inch deep — you can also accomplish this by sifting the growing medium over the seeds once the seeds are spread on the surface.
The container should be located in a spot that is at least 60 degrees. Consider using a heat mat for starting seeds to speed up and improve the rate germination.
The microgreens do not need fertilizer. A water mister is handy for moistening the soil without dislodging the seeds. Place a clear lid or plastic wrap that transmits light over the container to increase humidity until the seeds sprout. Ventilate the covered seeds daily, especially in bright conditions.
You can get consistent good results by growing the microgreens under grow lights for 12 to 14 hours each day. A fluorescent fixture hung on a chain works best, as you can adjust the level to keep the light at the optimum 8 to 12 inches above the seedlings.
A kitchen window is another option to use, though you may have trouble getting consistent results because of inconsistent temperatures due to drafts and the quality and quantity of sunlight in the winter. South and west exposures should work well for winter, and north and east for summer. Experiment some to see what works best for you, with the main thing being a large amount of bright, indirect light.
Most microgreens are harvested after seven to 14 days, when they are 1 to 3 inches tall at the first true leaf stage of development. Some are harvested at the seed leaf (cotyledon) stage, which is the first set of leaves to emerge at germination. The true leaves will be the second set of leaves that develop and will better match the appearance of the plant’s mature leaves.
Use a pair of kitchen shears to cut off the seedlings at the growing medium level as you need them. The microgreens will keep for three or four days in a zip-lock bag or sealed container in the refrigerator.
You should not need to wash the greens if you use an organic growing mix and clean scissors for harvesting. The plants are growing for a short period of time and in a controlled environment, so there should rarely be issues with dust or soil clinging to the greens.
Seed companies will have microgreen mixes and varieties available for you to purchase. A wide variety of plants will work to grow as microgreens, including beets, radish, celery, basil, dill, lettuce, arugula, chives and cilantro.
Plants in the Brassica genus are great ‘starter’ microgreens. Check the seed packet for tips on how to grow that specific green, as some greens are more finicky than others and need special attention. Arugula seeds, for example, do better if they are sown sparsely rather than crowded together. Germination rates that are above 95% and listed on the seed packet will increase your likelihood of success.
Tim Johnson is director of horticulture for the Chicago Botanic Garden in Glencoe.
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