THE WINES did not bear fancy labels or distinguished vintages. Indeed, one wine was bottled on Friday and the handwritten label was glued onto the bottle on Sunday during a car ride. The car ride led to the annual homemade wine competition of the D.C.-Maryland chapter of the American Wine Society, held in Seabrook, Md.

None of the 20 or so contestants was a professional winemaker. Yet most of the entrants grew their own grapes; and there was no sign of grape juice concentrate, the staple of many less-dedicated home winemakers.

Grape varieties ran the gamut, the winner being a marechal foch its producer, Joe Stielper, called Christmas Red.

The backgrounds of the winemakers were as varied as the grapes they bottled. Stielper, who had another of his reds come in third, is a broadcasting engineer. Walter Deshler, whose seyval blanc won the white-wine competition, is a professor of geography at the University of Maryland. Both have been growing their own grapes in southern Maryland for a number of years. Second in the white-wine competition, also with a seyval blanc, was John McGrew, a plant pathologist with the U.S. Department of Agriculture, who has an experimental vineyard in his backyard. Second in the red was Charles Franklin, an engineer who entered a de chaunac made from grapes purchased in southern Pennsylvania.

The national competition will be in Philadelphia in the fall.