Assorted microgreen trays.
From left: Mushroom soup with beet microgreens. Cowpea microgreens. Cabbage microgreens over pickled onions, pork and polenta.
Microgreens are young, immature edible seedlings typically harvested seven to 14 days after germination. Most microgreens are started from vegetable and herb seeds. Unlike traditional gardens, microgreens are a quick crop requiring minimal investments of time and space. The main differences between microgreen cultivation and traditional gardening are most microgreens are grown indoors or in climate-controlled environments and microgreens are densely planted, whereas vegetables and herbs in traditional gardens are spaced out for mature size, and microgreens are harvested at a juvenile growing stage.
Growing microgreens gives people access to fresh, nutritious greens year-round without needing garden space. Microgreens can be used in the same context as traditional greens and make great additions to salads, wraps, sandwiches, smoothies and as garnishes. Microgreens serve as a great source of fiber, essential minerals, vitamins and antioxidant compounds. They also add color, texture and flavor to many dishes (Xiao, Z.; Lester, G.; Luo, Y.; and Wang, Q. (2012). Assessment of Vitamin and Carotenoid Concentrations of Emerging Food Products: Edible Microgreens. Journal of agricultural and food chemistry. 60. 7644-51. 10.1021/jf300459b. 2012; Di Gioia, F.; and Santamaria, P. (2015). The nutritional properties of microgreens. In: Di Gioia, F.; and Santamaria, P. (eds.), Microgreens. Eco-logica editore, Bari, (pp 41–47).
Light and Locations
Corn microgreens grown in complete darkness.
Corn microgreens grown in the dark (left) and in light (right).
Microgreens can be grown almost anywhere: indoors in front of a window, under grow lights, outdoors on a porch or in a greenhouse. Depending on the edible plant you are growing, microgreens can even be grown in a dark closet or drawer! Flavor changes can be found in edible plants when grown in the dark. Many consumers believe corn and sunflower microgreens purposely grown in the dark have a sweeter, more delicate flavor.
All shallow containers with drainage holes work well for microgreen growth. Growers can choose conventional seed starting trays or reuse containers often found in the household, such as produce clamshells, take-out containers or cookie trays. Just be sure if you are reusing containers to sanitize them between their original use and starting your microgreen seeds. Microgreens can be grown with or without soil. This publication will focus on microgreens grown in soilless media. Soilless media is basically potting soil. It is not the same soil as found in the yard. Rather, it consists primarily of organic components such as peat moss, vermiculite and perlite. Hydroponic pads or water retaining mats are two soilless options.
Recycled containers with added drainage holes.
Mustard greens seeded thickly into a recycled plastic cookie tray.
Microgreen Crop SpeciesMost vegetable crop species can also be grown as microgreens. Some common selections include vegetables in the brassica family, such as broccoli, cabbage, mustard and kale; legume family members, such as peas, clover, and beans; and aromatic herbs, including basil, dill, cilantro, etc. However, any vegetable or herb will work, as other common microgreens include beets, sweet corn, sunflowers, radish and many others. While most vegetable species are suitable to microgreen crops, vegetables to avoid include solanaceous crops (tomato, eggplant, peppers, etc.) The foliage of these plants has many trichomes (hairs) that would affect the mouthfeel of the consumer. Solanaceous crops also tend to build up solanine in their leafy tissue, which can cause stomach upset if consumed in high quantities. When selecting seeds, use fresh, properly stored, quality seed to achieve even germination and a dense crop. If using older seed, you may need to sow your seeds more densely to achieve a similar effect.
Swiss chard microgreen tray.
Seeding recycled microgreen trays.
Begin by filling trays evenly with moistened soil. Adequate soil depths typically range from 1 to 4 inches deep. Moisten soil before planting the seed. A good rule of thumb is when you squeeze the soil in your fist, water should barely stream out. The more uniform the soil surface, the more uniform your microgreen crop. Sow your seeds evenly over the soil surface. For the cell trays, count out desired seeds per cell, but in an open tray an even sprinkling of seeds over the soil surface will work fine. How densely you sow your seeds will depend on how quickly you intend to harvest your microgreens. Crops harvested at the cotyledon stage can be sown more densely than those intended for harvest at the “first true leaf” stage. Cover the seeds with a thin layer of soil and gently water. Heat mats and humidity domes are not necessary but can help speed up germination and retain tray moisture, respectively, and should be considered in growing microgreens in cooler temperatures or in cooler environments. If using humidity domes, check the trays daily as mold can quickly develop when air flow is restricted.
The soilless media does not need to be fertilized prior to planting. Additional fertilizer treatments are also not required as the plants are harvested at such an immature stage.
Microgreens are harvested at different stages based on crop and consumer preference. Generally, most microgreens will be ready for harvest between seven and 14 days after the seeds emerge from the soil surface. The two most popular stages of harvest are pre- and post- “true leaf” stages. Cotyledons appear first and are embryonic leaves. In dicots (most vegetable and herb crops), two rounded cotyledons will appear first opposite of one another. In monocots, such as corn, one cotyledon leaf will emerge, then the first true leaf. Experimentation is encouraged to find the stage that you prefer. Try consuming some of the microgreens when they only have cotyledons emerged and wait a few more days and eat them again to experience flavor differences once the first true leaf has emerged. Flavor preferences vary among people. Experiment a little to see what you like best.
When ready to harvest, use a sharp, clean pair of scissors. BONUS: Corn plants can yield a second microgreen crop when harvested above halfway up the plant.
Harvested microgreens can be stored for as long as two weeks in an airtight container in the refrigerator. For longer storage, wash only immediately before use.
Are you experiencing uneven germination? Many factors play into uniform growth.
Harvesting corn microgreens with clean, sharp scissors. Photo by Kaylee Deynzer.
Mustard green microgreens with cotyledons (round leaves) and first true leaves (lobed leaves).
By harvesting the corn microgreens toward the top of the plant, the corn will continue to grow a second crop!
Grow lights were placed too close to seed tray. The outer plants stretched toward the center, while center plants were over exposed to ultraviolet light, stunting their growth.
Grow lights to supplement lighting are placed at least a foot above trays.
Mustard green microgreen tray. Photo by Kaylee Deynzer.
Harvested mustard microgreens.