How far from a busy road is it safe to grow vegetables?

Question

I have had differing opinions on this topic and I am wondering what should be the correct thinking. One person has said the carbon monoxide would make certain leafy vegetables unsafe to eat. My concerns are from when leaded fuel was used if this would be in the deeper layers of the soil. The road in question is two lanes in each direction and probably 4 feet above the potential garden site. One section is 10 to 15 feet from the road slightly above the ditch. The rest is about 20 to 25 feet from the road.

My thinking was the section 20 feet from the road should be safe since it was unlikely touched by road run off. The section closer to the ditch is of most concern to me. The grass, weeds, and trees love the conditions so it can't be too bad, right?

The road is busy at times during the day but not like an interstate highway. During off hours you are lucky to see 5 cars go by in a minute. Also the road may be young enough that it only had a few years of leaded fuel use but I am not sure of the age.

Answer 1

I think 100ft

Answer 2

Eliot Coleman, one of the premiere organic growers in the USA says at least 250 feet form a road. Organic regulations say at least 50 feet. I think at least 200 feet and that is if you are on the west side of the road (the direction of prevailing winds in most of the US). if you are obn the east side than the winds will blow fumes further onto your land than if you are on the west side.

FYI there is still lead in gasoline along with many other poisonous chemicals.

Answer 3

My grandparents had their garden on the other side of the ditch along the road.  They live on a fairly busy county road.  They never had any problems.  It is about 15-20 feet away.

Given the amount of traffic on your road and the fact that they cars are in the open are, you are going to have no problems.  Grass and other plants are able to grow close to the road and garden crops are no different.