While the hilly topography, prevalence of non-prime soils and lack of reliable water supplies are deterrents to more intensive agriculture like row crops, some areas in Marin that are rich in alluvial soils support diverse vegetable and specialty crops. Marin's coastal agriculture is well known for its quality grasslands, due to foggy, moist conditions that keep the grasses green much of the year and make them well suited for grazing dairy, beef cattle and sheep. About twenty percent of the Bay Area's milk comes from Marin dairies. Milk and milk products have dominated agricultural sales in Marin for over 125 years. Since 1983, the Marin Farmer's Market has helped connect consumers directly to farmers and their produce.
Several nurseries grow many crops, from roses and iris to heather and native plants.
Several ranchers are experimenting with growing cool-weather wine grapes and are hopeful of future market potential. Nicholas Turkey Breeding Farm near Tomales is part of a Sonoma-Marin operation that supplies half of the worldwide demand for fertile turkey eggs for hatching. There are approximately 121 dairies in Sonoma and 50 in Marin. Among the 43 counties in California that produce milk, Marin is ranked 13th. Marin and Sonoma farmers share many things in common, from family relationships to agricultural suppliers.