The concrete mixing troughs are great! I've been usung a couple -- without holes -- on the light shelf to "wake up"amaryllises, dahlias, and now caladiums. When the amaryllises started sending up a flower stalk, they got potted and brought upstairs... They tend to wake at different rates, so blooms are spread out all winter this way. You can speed them up with heat and slow them down by putting the tray on the cool concrete floor.
I'm thinking of burying a no-hole trough or two for plants that like it really moist. For just a few bulbs, the oil change pans from the dollar store are really great, too. I used them as deep saucers under indoor containers this past winter.
