My first real taste of microgreens— fresh, spicy daikon radish at a local restaurant— inspired me to try growing them at home. This article outlines basic information on microgreens, and gives detailed, step-by-step instructions on how I grew my first harvest.
Microgreens are full of flavor, color, “tooth” and nutrition. USDA studies have shown that microgreens contain “considerably higher levels of vitamins and carotenoids—about five times greater—than their mature plant counterparts.” Both sprouts and microgreens are extremely nutritious. And, I’ve learned, they’re quite easy to grow indoors. They are especially welcome in the winter months, when there’s less outdoor gardening and more time spent indoors (growing microgreens could be an excellent family project).
There is some inconsistency in microgreen terminology (and even spelling; you’ll see both “Micro greens” and “Microgreens.”) Generally, there are three classes of “immature” greens, listed in order of development time: sprouts, microgreens, and baby greens. Sprouts are grown in water and harvested for root, stem and seed leaf. Microgreens are generally grown in soil (or grow mats). They are harvested for their above-soil stem and leaves (cotyledons and/or very early “true” leaves). Some cultivation methods require artificial light; the method I chose does not. Baby greens take the most time, need full sun or artificial light, and are grown for their developed true leaves. There are pros and cons to each method; as I researched different ways to cultivate indoor greens, I began to hone my “starter” wish list:
- Simple, inexpensive supplies: Since I was new to this, I didn’t want to invest in expensive speciality equipment, shelving, mats, trays, or grow lights.
- Fast and compact cultivation: I hoped to find a method that didn’t require weeks or more of growth, and didn’t take over our indoor living space.
The method that best fit my criteria was to grow greens in “soil” (actually a soil-less medium, see Supply List), in small inexpensive pans, with no need for grow lights. I followed the strategy described by Peter Burke in Year-Round Indoor Salad Gardening. He refers to his harvest as “soil sprouts.” They germinate in the dark for about 4 days, then are moved to the light for 3 or more days. They do NOT require full sun or artificial light like some microgreen cultivation methods.
I was skeptical that Burke’s method would work, but it was a great success, and also lots of fun! As a microgreen neophyte, I followed his expert recommendations carefully. Other gardeners might prefer different cultivation methods (grow mats, hydroponics) or different supplies (fertilizer, growing medium), but this method is how I got started– and hooked on– growing microgreens:
Supply List:
- 3×6” foil baking pans
- Measuring spoon
- Measuring cup
- Cups for soaking seeds
- 1 gallon plastic bags
- 1 gallon juice container
Extensive root system of mature greens - Small strainer (I used a fine mesh tea ball, especially helpful for tiny seeds)
- Scissors
- Newspaper
- Watering can
- Seeds: It’s best to use untreated (and organic) sprouting seeds. These are readily available online and in specialty stores. To keep initial costs down, I started with a few 4 ounce seed packets ordered online.
- Soil/Growing medium: Soil-less mixes are highly recommended. I used a commercially available mix that contains sphagnum peat moss (75-85% by volume), perlite, ground limestone, dolomite, and mycorrhizae.
- Organic fertilizer: I used compost and liquid sea kelp.
Step-by-Step Instructions:
Soak the seeds: For each 3” x 6” pan, use 1 teaspoon of small seeds or 1 tablespoon of larger seeds (small seeds include broccoli and kohlrabi; larger seeds include daikon radish and sunflower).
Place seeds in cups and cover generously with water. Soak for a minimum of 6 hours and up to a maximum of 24 hours.
Moisten the soil: Mix 1 gallon (3.8 L) of dry growing medium with 3.5 to 4 cups (829 to 947 ml) of water. This can be easily mixed (and stored for future use) in a 1 gallon plastic bag.
Soak newspaper in water: Folded, wet newspaper will be the final cover over the soil and seeds. For each pan, use 1 sheet of newspaper, and soak for 10 minutes or more in a bowl of water.
Prepare each grow pan: First place 1/2 teaspoon of liquid kelp and 1 tablespoon of compost in the bottom of each grow pan. Then fill each pan with approx. 1 1/4 cup (296 ml) of the moistened soil. Level the soil by patting gently. There will be about 1/4″ to 1″ of space from soil top to pan edge.
Drain and spread seeds: When seeds are done soaking, rinse and strain through sieve/mesh. For small seeds, I use the fine mesh of a tea ball. Spread the drained seeds over the soil. They can touch but shouldn’t overlap.
Cover the soil and seeds: After the newspaper has soaked about 10 minutes or more (see Step 3), fold it so it tucks into the pan, and covers/makes contact with the seeds.
Place pan in the dark: Place finished pan in a warm, dark place (I used a storage chest) for about 4 days. The newspaper cover will help provide darkness and moisture for the seeds. As they germinate, the seeds will actually push up the newspaper (see photo below).
Move pan to the light: On day 5, remove the cover, water the soil (a few tablespoons) and place in a windowsill. The leaves will look pale and yellow, but will “green up” once placed in light. Leave in light for 3 or more days. Water the pan (a few tablespoons) once each day. After about 3-5 days the greens will be ready to harvest (Burke notes that you do NOT need a south-facing window to get adequate light.) Cut the stems above the soil line, rinse, and enjoy! Compost the remaining soil.
Final Notes: I loved growing micro greens and plan to continue throughout the year. While I found the 3 x 6″ loaf pans to be a great fit for my windowsills, they do limit the harvest amount. Burke notes that for his larger family, he grows 5 small pans daily. This provides them with an ongoing supply of fresh greens. Larger trays would of course be another option, but they are more cumbersome. Another reason I opted for the smaller trays was to limit possible contamination (such as mold), but this hasn’t happened so far.
Photos: All photos by Meg Norling
Resources:
Bachman, G. Microgreens. 2021. Mississippi State University Extension. https://extension.msstate.edu/southern-gardening/video/2021/microgreens
Burke, P. 2015. Year-Round Indoor Salad Gardening. Chelsea Green Publishing.
DelValle, T. 2017. Microgreens. University of Florida. https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/microgreens.html
Di Gioia, F. 2020. The ABCs of Microgreens. Penn State Extension. https://extension.psu.edu/the-abcs-of-microgreens
Horney, J. 2022. Grow Microgreens At Home. Purdue University Extension. https://extension.purdue.edu/news/county/allen/2022/02/grow-microgreens-at-home.html
