I'm with stone on the radishes - they aren't worth the effort. The ones you can buy at the store will taste as good or better than what you grow. That's the only reason to grow your own veggies for me - fresher and better taste.
I have really terrible soil in a garden space with large trees all around it, so I have resorted to growing all my vegetables in containers. The largest pots you can handle will give you the best results, and not too much of a chore for watering. You must use potting soil because other soil will compact and not retain enough moisture or air spaces. Potting soil is mainly organic material that acts like tiny sponges, fibers expanding when wetted and contracting as they dry to leave air space.
My kids found Earth Boxes for me, and I must admit most of my harvest comes from them now. They are a self-watering container the shape of a large window box, and come with casters which is handy if you are using them on a paved surface. They will hold a 3ft. row of beans nicely, OR 3 or 4 tomato or pepper plants OR 3 broccoli/cauliflower/cabbage plants or a row of peas or . . any combo thereof. Whatever else you like, but don't crowd. Using the fitted plastic cover once you have planted your Earth Box makes them extremely water-efficient, and there is no weeding and very little problem with pests as well. Once you get them planted according to the directions, all you need to do is make sure they are watered, and wait for harvest (well, you might have to support your plants with some stakes or cages . . ) Here's a picture of one of mine:
