While I'm not disagreeing with any of the information already give here, and I whole heartily agree that weed free is (near on) impossible, you may wish to read up on "Soil Solarization"soil solarization for future reference, or at least be aware of this technique:
- Soil solarization via Wikipedia
- Soil solarization - Can You Solarize Garden Woes Away? An article on soil solarization: Can You Solarize Garden Woes Away?
