Begonia

If you are open to perennials there are several that will tolerate or prefer shade. It would also depend on how big the boxes are.

Thanks for the input.

My Window boxes are approximately 4' long 1' wide and 5" deep

I am trying to stay away from perenials as they are kind of pricey for window boxes. I tried a few perennials in my pots last year, which looked very nice, but the plants out grew their pots before the end of the season, and were pretty much dead by the time I tried to replant them into my garden. It was a waste of time and money. I would really like to stick with annuals if I can.

I will definitely try the Begonias.

Thanks so much for your input. It is greatly appreciated.

I wonder if torenia (wishbone flower) might work. It's an easy plant with lush foliage and gorgeous, non-stop flowers. It's a little short (it creeps in a gentle sort of way)--maybe 6"? It's grown for me before on a balcony that received 3-4 hours of early morning sunlight but it also does well (as I recall) in complete shade, so it might have the range of tolerance you're looking for.

As a general rule, plants with broader leaves will work well in areas that are bright not with no direct sun. I don't know if you've tried new guinea impatients. They seem to do well for my north facing balcony that gets bright indirect light all day. I am also trying this new vine called Yellow Archangel (Lamium galeobdolon) that is suppose to do well whether it's in full sun or full shade. Fuchsia should also do well in a bright but not sunny location.

Nixon

I was also going to suggest New Guinea impatiens - I used them on my shaded front porch with similar light to yours and they did MUCH better than the normal ones.

You might consider some caladiums for height and torenia for low growing and flow over the side effects. Maybe whiskey begonia white flower,red leaf with red caladium or white caladium with red flowered,green leaf begonia. Juat a couple quick thoughts.
Happy Growing David

Oh for heaven's sake -- stick with the coleus! It's the only plant that will really be happy there and will give you lots of color. Pinch and pinch and pinch some more and mix up folaige color/varieties. Trust me, I've a similar situation and have tried most everthing. You can also get ipomea to grow but it is again, just foliage color. For annuals - spring pansies but not much else... You can also get ferns to grow but (again) no flowers. Accept the coleus and enjoy the show -- your neighbors will

Have fun.

How often do you water? I have a similar situation, and I now have self-watering window boxes. Once I started keeping them well watered whatever I planted did fine. Impatiens especially like a lot of water.