I'm going to say the obvious and that is, put drainage into the planters! Otherwise it's hit and miss between their suffering drought, and the compost going noxious because it's waterlogged.

I suggest you read Vicki's blog on Heuchera. They are specialist growers, and keep the national collection. She has really good advice on care of Heuchera and touches on watering.

Thanks Bamboo point taken.Thanks Doriac,will do.

They will not live long in a planter that is not well drained
as Bamboo says it is a much better idea to make some drainage
Waterlogged is the kiss of death for Heuchera, Heucherella and Tiarella.
Only water when they start to feel dry
If they get too dry you can tell as they start to look tired then wilt alittle
Dont leave them every time to wilt though as the leaves become marked.
Hope this helps :)