I set up a bowl full of marbles to provide water for my bees last year. It’s very pretty and it works, but I’ve recently switched to using a chicken waterer instead:
The bowl full of marbles isn’t difficult to maintain, but the I prefer the chicken waterer because, for me, it’s more practical.Postscript (10 days later): Now that we’re at Newfoundland’s height of summer (I guess), the bees are on the chicken waterer all the time and seem to suck down about a litre of water every two days. At any rate, that’s how often I refill the Mason jar. A larger bucket-sized chicken waterer would probably work too.
See Watering Bees for an overview of several watering methods.
I’ve found that a shallow container of rocks/marbles runs out of water pretty quickly. That chicken waterer looks highly practical — holds a lot of water & doesn’t allow mosquitoes to breed.
Although my bowl of marbles was easy to fill, it dried up quickly and I often didn’t notice it was empty. The chicken waterer is easier to monitor (for me) and one big Mason jar full of water seems to last a long time.