A microgreen tray is a shallow container used to grow microgreens in a thin layer of growing medium. The tray provides the structure that holds the medium, retains moisture, and supports the plants during their short growth cycle from seed to harvest.
Standard microgreen trays are flat-bottomed plastic or metal containers, typically 10 by 20 inches (the “1020” nursery flat), with a depth of one to two inches. Some trays have drainage holes for bottom-watering setups; others are solid for use as catch basins beneath a perforated growing tray. A common two-tray setup pairs a holed tray (holding soil and seeds) with a solid tray beneath (holding water that wicks upward through the drainage holes). This arrangement provides consistent moisture without overwatering the surface, which reduces mold risk.
Material matters for food safety. Trays rated for food contact avoid leaching chemicals into the growing medium that could transfer to the harvested greens. Reusable trays should be sanitized between batches — warm soapy water or a dilute bleach soak followed by rinsing is standard practice. Some growers use disposable fiber trays to avoid sanitization, trading material cost for labor savings. The choice of tray depth, drainage configuration, and material affects moisture management, root development, and how easy the microgreens are to cut cleanly at harvest.