Betsy - you are setting yourself up to have a challenge here...doesn't mean it isn't doable but it is challenging...they don't like their roots damp all the time, so having some way to keep that from happening is important. Bev suggested spraying them lightly with a water bottle, that is a good idea, in this way the soil won't get too wet, but it means doing this every day or every other day, so it isn't an easy thing to keep up, but if it is all somewhere convenient it can be a meditative moment
Keep us updated! Another thing you could do would be to place the semps in a square pot that raises them above the tray...even using a plastic container which you could spray paint, and poke lots of holes in the bottom.