Question
dear Bakerplanter,  I would like to grow something(s) edible and pretty to look at in a window box outside a southfacing window.  I'm in SW France, equivalent to zone 8 I think.  We will have hot summers but its still frosty at night.  Could you suggest something that will give a good display and provide some sustenance.
many thanks  Judy pickering

Answer
Any vegetable that will grow in the ground can be grown in a container. But some crops, such as corn and pumpkins, may not be worth the effort. You don't have to stick to the so called dwarf varieties. Most standard-size vegetables are suitable for containers. For beans and carrots, plan to sow the seeds directly in the soil-filled container. Transplant the other types from seed starts or from plants purchased ready to plant.
The container should be around 18 inches deep. If your window box is small, it will not produce enought to make soup, but it will be a fun project.The larger plants, such as, cucumbers, eggplant, peppers, squash, and tomatoes, should be planted with one plant per pot, so I would not put them in your window box. For your window box, a mix of vegetables and flowers would be pretty. Some Alyssum to hang over the edge and Marigolds for sunny yellow. How about a lettus mix. They come in lots of colors and you could cut off the leaves as you need them for you salad.
If you have more containers, you could plant the rest of your salad in them.
Buy the best potting soil you can afford. Add time release fertilizer, and a water holding POLYMER to the soil. Give them a boost by applying fish emulsion every two to three weeks. Don't let the soil dry out, especially when it is hot. You may have to water twice a day. If the temperature is over 95F degrees, don't fertilize.

How exciting to write to someone in France. I, too live in a zone 8. I usually wait until the end of April or May to put out my "tender" plants. I hope I was able to help you. If you have further questions, let me know.
bakerplanter