I plan to use this for growing small amounts of cat grass (its actually Wheatgrass) for my cat. The default diameter is 84mm by 15mm high. It is parametric so you can change the diameter, height, hole size, hole spacing, etc. using Customizer.

There is also a "basin" piece that fits underneath to hold water. My test print seems to be holding water so far, but if your printer prints a bit "loose" you may need to coat it to make it waterproof (spray with lacquer maybe?). To make the basin, set "basin" to 1 in customizer. The code adjusts the size to fit the tray without changing the settings. You could also change the wall thickness and bottom thickness to make it more rigid and possibly more watertight. The inner diameter of the basin is 2mm more than the outer_diameter variable for a loose nesting fit.

The default wall thickness is very thin in an attempt to use as little filament as possible. Changing the wall thickness to 2mm will make it relatively rigid. If you change the wall thickness, you should probably change the bottom thickness too.

[update 3/14/2020] Fixed an error in the basin code. Uploaded a thicker walled basin STL