Are these dishwasher safe? I've purchased 20 of them and would love to know.
Yes these 1020 trays are top rack dishwasher safe.
Are these colored trays the same, structurally, as the 1020 Trays - Extra Strength that come in white and black?
Yes they are. The only difference between the colored trays (including white) and the black ones are that the colored ones are made from virgin plastic in order to produce a consistent particular color.
Are the blue color trays a medium blue as I see in the pics? Or is it different... baby blue, or aqua, or navy, or teal, or... ?
The blue 1020 trays are medium blue as in the pictures (almost like a cobalt blue)
I am new to gardening.Are people buying the tray with the holes for drainage and putting that one in a tray with out the holes to catch the water?
Yes that is a popular way that people use our 1020 trays. They will use the 2.5" deep mesh tray with a 1020 tray. Or they may use our microgreen tray with holes and our microgreen tray without holes.