Micro greens can be a rich source of natural nutrients such as sulforaphane. While you can sometimes find micro greens in the local grocer or farmers' market, you can assure yourself of a constant supply by growing them yourself. There are many videos and websites that show how to grow them. Here I document how I grow them with very little effort for my family.

Supplies

Broccoli seeds and water are the primary ingredients. You will also need:

Growth medium: coco coir https://www.amazon.com/gp/product/B06ZZXZQWW

Growth medium binder: psyllium husks - buy the cheapest

Growing trays - https://www.amazon.com/gp/product/B0BQBRY211 Get twice as many trays as you expect to be growing since you will need one extra each for weighting, and keeping in the dark.

Full spectrum grow lights - https://www.amazon.com/gp/product/B09BQGVQLW

Water sprayer - https://www.amazon.com/gp/product/B07VLWCG3N

Broccoli seeds - https://www.amazon.com/gp/product/B085BWXTBR

Assorted scoops and/or measuring cups

Large mixing bowl

Step 1: As Simple As I Can Make It

We wanted to eat micro greens on daily basis and we couldn't reliably get them at the local grocer. Quality and price were also issues, so I figured out how to grow them in a small space with very little effort. I did look at lots of videos and web sites, and experimented a little before I settled on a repeatable method that took very little time and maintenance. The basic steps are:

Prepare trays of growth medium.
Spread seeds and soak them.
Weighted trays sit in dark for two to three days.
When roots appear, and weights are pushed up, add water and cover with inverted trays or keep in the dark.
When sprouts are above level of tray, add water and remove covers. Place in light.
When you have a solid mass of bright green growth, harvest.
Rinse, spin dry, and store.
Dispose of media on compost pile.
Start over.

This provides my wife and I enough micro greens to add to soups, salads and sandwiches until the next batch is done. Each batch takes about seven to nine days, depending on temperature, seed batch, and other unknown factors.

Step 2: Preparing the Soil

Anything that grows requires a supporting medium. Usually that's soil. For micro greens I've tried various options, from paper towels, to silicon rubber mesh, and potting soil. I settled on coco coir. This is finely chopped, dried coconut husk. You can buy it loose from a gardening supplier, but I found it most economical and convenient to buy it in bricks. I do have to hydrate and break up the bricks before I can use them. I do this by chopping them up a little, putting them in a plastic container and pouring 3 cups of hot water over the chunks. I close the container and let it sit for a few weeks. That gives the coco coir time to become evenly hydrated, and you can break up any remaining chunks by hand. The water will be totally soaked up and you will end up with something the consistency of coarse sawdust. I usually keep one or two bricks worth in a 5-gallon bucket.

During my early experiments I found that greens would pull loose from the coco coir as I tried to harvest them. I discovered that if I add a little bit of psyllium husks to the coco coir, they act as a binder to hold the roots down.

I usually prepare three trays at a time, which provide me with enough greens until the next batch matures. Here I will describe the quantities I use for each tray.

In a large mixing bowl I put 2 cups of coco coir, along with 1 tablespoon of psyllium husks. I thoroughly mix this while its dry, otherwise the psyllium clumps into a gummy mass.

Add 1 cup of water. Stir thoroughly so all the coco coir is wetted. Let this sit a few minutes to soak up the water. Prepare your tray.

Spread the damp coco coir evenly in the tray. I use a spatula for spreading and lightly tamping.

Step 3: Planting the Seeds

For each tray I use 1 tablespoon of seeds. I try to spread these as evenly as possible. It can take a little practice, since the seeds are like little marbles.

After spreading the seeds, I spray the tray thoroughly, until the surface glistens with moisture. Be sure the sprayer isn't so strong it moves the seeds or coco coir around. I found a small pump sprayer very useful for this.

Step 4: Waiting

Once the tray is prepared, it goes onto the rack. To ensure the seeds grow into the soil properly, the seeds are covered with a weighted tray. I found that two pounds is enough. I mark the start date on a note, and I leave them alone for two days.

After two days, there will usually be roots showing through the screen, and the weighted tray will be pushed up. At this point I add enough water into the green tray so it just touches the white screen. This will keep the roots wet without flooding the coco coir. The sprouts are covered to keep them in the dark. This encourages them to elongate for easy harvesting. I actually grow the sprouts in what used to be a darkroom.

After about two more days, the sprouts should be reaching above the edge of the trays (see last picture above). They are now ready for light. I use a timer to give them 16 hours of light each day. I also add water. From here on I check them daily to be sure the roots remain wet, and to await the harvest.

Step 5: Harvesting

When the greens are truly green, and have grown into a dense canopy, they are ready to harvest. I just grasp a bunch and use a sharp knife to cut them. Scissors can also work. Then I rinse them to remove any "dirt" and seed shells, and use a salad spinner to dry them. I place them in containers lined with paper towel so they stay crisp, and keep them in the fridge.

In the last picture you can get a sense of the mat that is formed with the help of the psyllium husks.