City families are being sought to spend a weekend in October on a working farm in Virginia's Shenandoah Valley and then be hosts to the farm families later in the year.

The City-Farm Swap exchange program, set up by the Agriculture Council of America, is intended to increase understanding between farmers and consumers. "We've found the City-Farm Swap to be very effective in helping farmers and city people of out how much they have in common," said Allie Smith, chairman for the Rockingham Farm Bureau Association Women's Committee which is cosponsoring the program. Mrs. Smith and her husband, Everette, are poultry and dairy farmers from McGaheysville, Va.

City families take part in daily farm activities, from milking the cow's to discussing the farmer's bookkeeping methods, to learn what's involved in food production. The farm visit is scheduled for the weekend of October 14, 15 and 16. Later in the year, the matched family will visit the city family on a weekend prearranged by the two. Program participants are selected and matched on the basis of the family size and interests.

The swap is in its third year in the Washington area, and simiral programs are conducted by ACA in New York City, Kansas City, Minneapolis and Chicago. City people interested in the program should write to the City-Farm Swap, P.O. Box 23421, Washington, D.C. 20034.