Small space can produce big results. Even a small patio garden can supply a decent amount of produce. The biggest problem with a patio is you can't change the position that it points. How well your garden will do will depend on how much sun it gets.
For the sake of this post making sense we should establish the fact that the reader lives in a condo and has a small patio off their sliding glass door. My sister lives in a condo and is on the third floor and directly off her living room she has a small outdoor patio. The climate she lives in has all 4 seasons. With this environment she has a limited growing season.
Sun requirements
Knowing the direction your patio faces will give you an idea of how much sun your plants will get. Read the plant's requirements for sun. If you are mostly in the sun when it is warmest, the sun loving plants will do best. Where as your neighbor on the other side of the building facing a different direction, with the same plant could end up with not as good results.
If you have your heart set on certain plants and want to give it a try, even if the suggested conditions are not in your favor. Well there just might be a few things you could do. Let's say you want to warm up your patio area. You could get a heavy gauge clear plastic (like what you can buy by the yard at Tap Plastics). Attach this to the inside of your patio area with clear fishing line, after punching holes in the plastic. This would act like a little green house, protecting your plants from cold winds. It would add a few degrees to the area. You could put it on all 3 sides or just 1 side, depending on what you feel the need might be.
Containers
You want to get more in a small place and of course we are going containers. But why not a strawberry planter? It is not just for strawberries. Any vertical type containers would give you more planting space or even just having stands that has shelving for pots.
What to plant?
Well this is a great opportunity to do companion planting, this will protect your plants and give you extras for the kitchen. If you want to grow lettuce, then plant some a few weeks apart so not all of it matures at the same time. My dad used to plant lettuce in rows and as it started to grow he would thin it out and we would have young tender leaves to eat, which would extend the growing season. Plant some herbs in amongst the vegetables. Marigolds are also great for keeping the pests away and you get the added burst of color.
Plants or seeds
In some cases you might just want to buy your plants and other cases you might want to buy the seeds. Just check the space requirements for each plant you want. Not a good idea to plant zucchini on your patio; unless you have the space and really love the vegetable!