Just about any kind of wide, shallow tray will work for growing. We found that pie tins work especially well.
Instead of traditional potting soil, we used [a href="http://www.gardeners.com/buy/coir-seedstarting-mix/40-135.html"]Eco-Co® Coir Seedstarting Mix[/a]. It comes in a compressed brick that you reconstitute with water, which makes it convenient and easy. After you harvest, it can be composted. Whatever you use, the mixture should be moist, but not soaked.
A shallow layer of soil is all you need. We used an inch of coir, packed just a bit.
We chose a blend of seeds that was selected for growing as microgreens. Sprinkle the seeds on the soil surface.
Cover the seeds by sprinkling them with a thin layer of soil. Use your hand to firm the soil surface.
Water the seedlings with a sprayer. Cover the tray with a plastic dome or plastic wrap.
When the seeds have germinated, remove the cover. If you're growing on a windowsill, rotate the trays periodically so seedlings don't lean into the light.
Water regularly, making sure the seedlings don't dry out. Depending on your soil mixture and light, you might have to water every day or so. You can use a sprayer or a watering can.
If you use a light garden, your microgreens will grow faster.
Microgreens are fragile, yet resilient. This tray of seedlings collapsed after going without water for too long. After we watered them, the tiny plants rebounded quickly.
The crop is ready to harvest when "true leaves" form. Plants are usually about 2" tall.
Use scissors to trim the greens right at the soil level.
Rinse the harvest and it's ready to eat. Use it to garnish entrees, or mix it with full-grown salad greens.
Photos: David Grist and Deborah Miuccio