There was a DG "person", aggravating as could be, who wanted to raise her amaryllis so I told her "One good watering, then NO more water until you see a stalk and NEVER water from above". All went well until she "felt sorry", watered from above and got gnats.
I keep the smaller, potted coleuses, in either a tray or on a boot tray - about $3.00 from Christmas Tree Shops. It's easier to see if the tray is damp so overwatering is avoided.
Boot tray:
