Trays, domes and inserts are very useful tools for a large number of applications in the garden, and particularly indoors where spills and dirt are a bit more of a hassle to deal with!
Trays, also called 1020 trays (for their dimensions), can be used to hold a number of plants and catch their run-off, eliminating the need of small individual saucers. They are perfect to transport a number of small plants at once and to start young plants or microgreens.
Domes are designed to fit on top of trays and hold the humidity inside to increase germination rates and the propagation of cuttings.
Inserts are placed inside of trays to divide them in a number of cells and facilitate germination by separation!