Anney - I love to use nasturtiums for that reason - flowers are edible for salads and stay beautiful until frost. They grow great in containers as well.

There are a host of mini- or dwarf crops suitable for container growing. Here's a cut and paste link to some varieties I have grown over the past 25 years:
http://www.harvestwizard.com/2008/12/dwarf_and_miniature_vegetables.html

Here is a link that might be useful: HarvestToTable.com

Virtually anything can be grown in that depth of potting mix. Total volume of mix (for water/nutrient retention) is much more important than depth.

There are some obvious exceptions such as potatos, but other than that the 8.5" of depth won't limit anything.

If my math is correct your container holds approx 2 cubic feet of mix or 15 gallons. That's enough for even a large tomato plant.

Those dimensions are also very similar to commercial self watering containers such as EarthBoxes and there isn't a veggy known to humankind that can't be grown in them (again, with the obvious exceptions like carrots and potatos)

ajax

Good suggestion! I've been thinking about some dwarf marigold seeds that I have for that area, too, and the two might really color-blend well. I hadn't thought about edible flowers, but that sure works with lettuce, doesn't it?

stephen

Thanks for those links. Some neat small veggies at the cut&paste link. I didn't say, but growing vegetables in containers is a very minor part of my gardening effort -- I have lots and lots of room to plant in the soil and must guard against planting more than I can handle there!

I do grow all my lettuce in containers, since they're on the deck and I can move them into shadier spots during the bad heat of summer. I've had pretty good success doing this for years. But the onion containers are new this year, and I sure do hate the thought of their being idle for half the growing season! The 8.5" depth is not great for a lot of vegetables, though maybe good spacing would compensate some.

ANYWAY, I'm also interested in herbs, as well as flowers, that I could plant after the onions are pulled. Some herbs don't do well in the heat, and some that do get to be very large. My Mammoth dill grew to be more than five feet tall out in the garden last summer! I just need to find some that won't outgrow those containers.

JAG

Sorry, missed your comment before. You've sure got good 'rithmetic skills! Each of the containers is half a 30-gallon Sterilite bin, and I have four halves, though they aren't self-watering, just close to an outside faucet. That's about equivalent to one 8' x 1' bed! I've been thinking of putting two bell pepper plants in one of them, thinking that would be roomy enough, and maybe June/July wouldn't be too late to put good-sized transplants into it. (That's the other consideration -- when I can plant something after I pull the onions). Or maybe a couple of eggplants that I haven't planned to set out in the garden. We don't eat many of them.

There are definitely possibilities, but to recognize them, I suppose I'll have to think beyond "small plants".