This was an experiment to create an aeroponics microgreens grow. The idea is to use a silicon or stainless steel mesh with holes small enough to keep the seeds from falling through. Then a top is a placed on to act as a weight (pushing the roots down) and to keep the water that is sprayed through nozzles (every 15 minutes for 1 minute) from escaping.
It was successful for the first couple of runs, and was very easy to harvest (no coco coir, or other medium to clean off) and easy to scrub the grow plate off afterward.
The one downside was not using very clean water, I re-used a bucket for the water to drain into, and dirt continually got into the spray nozzles, and clogged them up. Would need a way to ensure the water was filtered before it enters the spray nozzles for a fully working setup.