I'd suspect that most of the water is just running out the bottom and they are suffering from lack of water, even if being watered frequently. Unfortunately, when some composts dry out, it's hard to get them to absorb water again. If you can put your fingers a few inches down in the pots, you can feel if the compost is damp. Assuming the pots have drain holes in the bottom, it would be pretty impossible to overwater.
Is there any way of getting large trays to put under the pots, and then get someone to lift them on? That way you can see if there is enough water - the excess will collect in tray and can gradually soak up into pot.