Keeping your home well maintained is the best way to preserve your most expensive investment:
Today we look at garden beds. Our housing stock is old. Most of it was built before 1978, which is when we stopped using lead based paint as a country. Lead paint, when exposed to rain for many years, runs off and into the soil. If you're laying out your garden, especially your vegetable and herb garden, DO NOT put it by the house. That soil is likely contaminated with lead.
Additionally, make sure you use wood that's not been treated. I've seen several houses lately who's vegetable boxes were built with pressure treated wood. Granted, this wood will last much longer than cedar, but it will also contaminate those tomatoes of yours with Chromated Copper Arsenate, Alkaline Copper Quat, Micronized Copper Quat, Copper Azole and Sodium Borates. I couldn't tell you what these things are (I pulled them directly from the wood manufacturer's website) but I'm positive you don't want them leaching into the soil you've painstakingly nurtured your food in.
As always, let me know if you have any questions, and happy gardening!