Growing microgreens at home can be a fun and easy hobby, especially during winter when a bit of fresh green leaves will be very welcome. The big difference between microgreens and sprouts is that microgreens have developed the first 2 true leaves of the plant, called cotelydons, whereas sprouts haven't developed leaves yet and often have the seed attached.

First: decide on a growing method.  I took the easy route and ordered the full hydroponic kit online; a bamboo box and lid, a plastic insert that keeps the water separate from the growing medium, a hemp growing mat, and seeds.  My kit included broccoli and arugula seeds, which we really enjoyed. Later I received chia microgreens (think chia pets) which were not a favorite in our house.  A crop of cilantro microgreens failed because we decided to take a trip and were away too long to remove the lid of the box and the whole crop was moldy. Later when I was cleaning out my garden bed in the backyard I found a lot of arugula seed pods and harvested those to grow microgreens.  If you are looking for a way to add plant-based nutrients to your diet, then a little bit of crunchy microgreens might be for you. This would also be a great science project or something fun to do with your kids or grandkids.

At this point, it is important to consider food safety practices.  According to an article from University of Nevada, best practices for hydroponic growers would include cleaning the container thoroughly prior to use, wash hands thoroughly, use only treated (city water vs well water) and preferably filtered water.  Scissors or other tools used to cut microgreens should be non-porous and sterilized before every use.  Because microgreens are eaten as raw food, and grown in high humidity conditions, the possibility of the presence of pathogens is greater than for food that would be cooked.  It should be noted here that there were no food safety instructions in the package, so growers should do their own due diligence in researching safety practices before proceeding.

Following the package directions, I filled the plastic container with water, laid the hemp mat on it and let it soak up the water.  A hemp mat is a soil-free growing medium, sort of like a coir mat but made with hemp fibers.  There is no soil involved in this process, so themicrogreens do not have any soil clinging to them, which makes harvesting very quick and easy.  Next, I sprinkled the seeds on top of the wet mat.  I was uncertain how many seeds to use, so applied them very liberally, in case not all of them sprouted. 

Next the instructions said to cover the box ofmicrogreens with the included bamboo cover for 3 days with a corner left open so that air could circulate. The purpose of this step was to reduce bitterness in the greens.   I then placed the box in my south-facing garden window and made sure that it didn't get too warm in direct sunlight.

In 3 days I removed the lid, and noticed tiny light green leaves. The directions clearly described how to distinguish between tiny roots and mold.   After about a week the cotyledons were about an inch tall, then after about 10 days, they had grown above the top of the box (about two inches tall). I used clean kitchen scissors to cut the greens, and sprinkled them liberally on salads, sandwiches, scrambled eggs, and even pizza!  What a delight to have a fresh source of highly nutritious and delicious microgreens to add to our meals. 

An article published by the National Institute of Health reports a study conducted that outlines the comparison of nutrients in broccoli microgreens (grown hydroponically) versus the nutrition in mature broccoli. The study found higher concentrations of potassium, magnesium, copper and, zinc, in the microgreens than in the published standard amount of these elements in the mature broccoli plant

Resources:

https://extension.unr.edu/publication.aspx?PubID=3468

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5362588/

Definitions:

Cotyledon- a seed leaf that is distinct from the characteristic leaves of the plant (pg. 706 of California Master Gardener Handbook, Second Edition

Hydroponic-Plants grown without soil

Microgreens-cotyledons grown for consumption: taller than sprouts (about 2 inches)