6 hours of sun sounds like enough to grow almost anything.

I disagree. if it were 6 hours for six months, yes. But it is six hours for three months. I would concentrate on herbs, root crops, cabbage, greens. The fruiting plants will be limited. If you insist on fruits, I would go with zucchini and beans. You can however grow things in full shade in the winter, since it is Zone 9. Lettuce for example, and you will still have some herbs.

What time of day was this picture taken? Was it sunny?

That first photo was from the real estate company, so I don't know. Let me post a few that I took at 11:15 am, and it was sunny. Solar noon is between 1:00 and 1:30 pm this time of year in Barcelona.

Another.

Last one. These three photos were taken January 22nd.

Maybe not very related, but that area is absolutely beautiful. Its a shame you don't get more direct sunlight.

Sorry! I was thinking your winters would be too cold to garden.

I want to thank everyone for their help so far. It is such a beautiful space, and I too wish it got more sunlight. I would like to grow tomatoes, different varieties of peppers, and a lemon tree in addition to those plants glib suggested. There are two street balconies on the opposite side of the property which are southeast.facing and on a very wide avenue such that sun is not blocked much by buildings. Even with the very low sun in January, the balconies were getting four hours of sun, which I'm sure will increase in the spring and summer.

Looks very nice but lack of sun will probably hinder growth of plants that like a lot of sun like tomatoes & peppers.

From what I've seen of the weather in a Barcelona Summer you will be grateful for any shade you can get. I think you will be able to grow tomatoes without any problems. But even if you can't you will be living in a city with some of the most fabulous fresh produce markets anywhere.

At my house the north side is the spot that gets the most sun due to trees/buildings that shade the south side for most of the day. I grow plenty of vegetables with what I've got, which is fairly similar to you (sunlight hours-wise anyways). 6ish hours for 4 months (~120 days) I would imagine to be enough.

But like someone else said, the summer's heat may be a problem. Of course that's a pretty easy problem to handle by using the material used for row covers as a buffer and finding what cultivars are locally grown and proven in that environment. I've never been to Spain so I don't know what it's like, but I have been to Iraq and they grow plenty of vegetables in 120*F, so I know it can be done.

trained morello cherries, currants, strawberries, saladings, herbs