Hi there. I want to put a raised garden bed on top of a cement area we have in the backyard. This is the only area we have for a possible garden. I was going to get some cinder (cement) blocks and stack them two high for a height of 16" and maybe have a bed that is 3 feet wide by 4 feet long. I am curious about potential problems.

1) Drainage: I was just going to pile in the soil in between the blocks, directly on top of the cement. Since the cement is pretty flat, it seems like the water will not drain away from the garden bed. (I noticed some puddles that sat there for a day or two after a rain storm)Will that cause rotting underneath? Any other potential problems with that?

2) Sunlight: During the winter, this area does not get direct sunlight. I thought about reflecting the sun using the fence near it that gets a lot of sun (maybe I could paint the fence white) and some aluminum foil or other reflective material. If I can't make that work, I will only use the garden bed during the spring and fall seasons, when it gets direct sunlight. If I do that, what will happen to the soil that sits in there for six months of the year, unused? Will I have to replace it?

Although we would like to plant a variety of things, our main focus would be tomatoes, onions, carrots,and garlic.

Any other helpful tips would be greatly appreciated. Thanks a bunch!