How often should I water window boxes?

[Distel]

In the summer when they have hot sun on them (from about 2 o clock untill early evening), I water them about 1 litre every day. But how much and how often at this time of year when they have no sun on them. I don't want to over water them.

The boxes are about 2 feet by about 6 inches deep and wide. They have Forget-me-nots, Trailing petunias and Silvas in them (don't know if that makes a difference).

Thankyou to anyone that can help me x x x

If you have good drainage, ie;drainage holes in the bottom of the boxes and a layer of crocks at the bottom it should be quite hard to over-water as any excess water should drain out.Hope this helps.

I'd still water them every day; a small box dries out quickly even in less sunny weather.

Thankyou