It makes sense to have an agricultural zoning category in towns, rural areas, and cities where farming is an existing or desired land use for certain properties, and where a zoning ordinance is in place.
Determine with the current land owners where agricultural zoning is appropriate. Is it their intention to farm? Is the land itself appropriate to farming (i.e., not too rocky, not a cliff, and so forth)?
You have to ask this last question because in many states of the U.S., land zoned agricultural is assessed at a lower rate than land zoned for development, so someone may try to fool you about their intentions or even the appropriateness of agriculture at a particular location. If you are located in one of the low property tax states, do not assign that agricultural zoning just because Farmer Joe Smith is a guy you like.
Agricultural zoning can be a wonderful tool for communities that are trying to restrain sprawl. One of the causes of urban sprawl, after all, is jumping over exurban farms to allow urban development, in a pattern often called leapfrog development.
Almost inevitably, the spaces between the leapfrog subdivisions get filled in. So an affirmative statement of where you would like to retain agriculture is a great sprawl prevention measure. Sure, zoning is subject to change, but it requires a conscious effort of the community or an applicant.
We maintain that agricultural zoning is an asset to the farmer as well. It affords great protection against the neighbor who recently arrived from suburbia and is offended by barnyard noises, smells, and rhythms of day and night.
Of course, allow agriculture and all accessory uses and buildings common to agriculture. The language can be that simple.
However, because people are crafty, you may want to spell out these accessory uses, according to the type of agriculture common in your area. That might include horse barns, tobacco barns, pole barns, hog houses, granaries, and garages for farm implements, but not cucumber processing plants. It all depends on where you live.
Usually in agricultural zoning, you'll want to restrict processing of agricultural products beyond what is necessary to get them to market. It may be, however, that you want to allow certain minimal processing as a conditional use. An example might be small cheese-making operations.
Of course, you allow one farm house or maybe two farm houses; make the second house on a parcel subject to a review such as a special use permit if you think there is enough demand for and threat of urban development that you need to be careful about adding that second residence.
Then you also allow the customary accessory uses for the home itself, including a garage and a shed. You can provide that the second house be used only for family members or farm laborers.
You may be able to require that land not be subject to options to sell based on an urban use; be sure to discuss that one with your attorney.
You should require setbacks from other zoning districts for certain agricultural operations, such as chicken houses, or for all of them.
Actually it is the sounds and the smells, which can travel many feet, that often produce the conflicts between agricultural land uses and more residential ones. So assess your area's typical agricultural business realistically and figure out how and whether to require buffering.
The minimum acreage for a parcel in an agricultural zone should generally be quite large, as large as the smallest legitimate farms in your location.
If you want to encourage the development of cluster housing, or conservation subdivision, development, then you can vary your minimum lot size according to the way you'd like to see the conservation subdivision evolve.
Of course, just as in any other zoning action, avoid the appearance of spot zoning.
An Urban Agriculture Zoning Category
Especially in cities that have suffered population loss, but actually in many other cities also, people are contemplating urban agriculture. Reasons include a general trend toward thinking about environmental sustainability, a preference for reducing carbon footprint, worries about who has tampered with the food or what chemicals have been used, concern about the quantity of vacant land, or just plain thrift in the wake of a recession.
In cities, it's fine to have an agricultural classification, but
you probably would want to restrict accessory uses considerably more. Usually it's overkill to change zoning to accommodate someone who wants to start a community garden; see if you can allow a garden under a certain size as of right, or through a special use permit.
For a Broader Discussion of Rural Community Issues
For a discussion of rural zoning of an entire rural community, be sure to see the page on rural zoning.