There are many different methods you could use to find local producers - it often takes a bit more effort but can really make your food co-op stand out.
Searching on the internet
There are several websites you can use to search for local food, including the Soil Association’s Organic Marketplace, Open Food Network UK and Big Barn. These can be useful, although they tend to be consumer focused and so usually list more farm shops, box schemes and markets, and don't always say whether farmers supply wholesale. Also be aware that not all web listings are kept up-to-date.
You can also just do a general search on the Internet - including searching using Google Maps which will bring up results on a map. Try putting in the search terms 'local food' or 'fruit and vegetable growers' and then your county, region or town. This may also take you to other websites that list local producers.
There may also be local food directories that have produced specifically for your town, county or region, for example Sustain’s Good Food map for London. These usually list local producers selling direct to the public through farm shops, pick-your-own, box schemes and farmers’ market, as well as restaurants and food businesses providing locally produced food. These directories are often produced by councils, local food groups or environmental organisation, and if you don’t have access to the internet you might be able to find a printed copy by contacting your local council or asking in a library or tourism information centre.
Farmers’ markets and farm shops
Visiting a farmers' markets is a good opportunity to talk to local growers in person and see the range and quality of produce they sell. Visiting the nearest market will help you find producers who may be able to deliver to your area. If you do have a farmers' market in your town then stallholders may be willing to drop off to you on the same day as the market. You can find details of farmers' markets on the following websites and also by looking in local food directories or doing an Internet search.
Many farm shops supply some of their own produce, as well as buying from other local farmers and they may also provide a wholesale service or be willing to provide a discount if you order in bulk.
The Farm Retail Association has a map with listings of the 'best real farm shops and real farmers' markets' from across the UK.
Another (slightly cheeky) thing to do when visiting any other local food outlets including wholesalers, greengrocers or farm shops is to look on the sides of produce boxes, as these often have the contact details of farms on them.
Visiting farms directly
Not all food producers are listed online or in published food directories, so it may be a good idea just to drive or cycle around the countryside speaking to people in village shops, stopping at farms or wherever you see produce growing or ask who grows fruit and vegetables in the area. The farming world is tight knit and generally helpful and so they will probably know of other farms nearby. You should also ask your existing networks about any farms they know and you could also contact local agricultural colleges or places with land-based studies courses. You could do this at the same time as you are carrying out any food mapping or needs assessment. You may come across small-scale growers who may not be commercial farmers but will still have signs out saying they've got produce for sale.
It is a good idea to phone or email in advance of visiting, but if you don't have a farm's contact details there is no harm in dropping in quickly and seeing if anyone is available or arranging a meeting for another time. However, you should also consider that some times of the year are very busy for farmers. Try to be aware of the farming calendar, and avoid cold-calling during busy periods such as sowing, harvesting or lambing time. Always be prepared to drive away if you arrive when things are fraught or busy. Some farmers, particularly large organisations or Farm Managers, expect to be contacted for an appointment. Wet days usually mean less outside activity and probably more time to talk.
Contacting local food organisations
Local food organisations have been set up in many locations around the UK to support the development of the local food sector, for example Sustainable Food Cities.
Some organisations are government-funded bodies whereas others are smaller community-run networks and so they all focus on different activities. For example, some have helped develop farmers' markets, whereas others focus on trying to get more local food into publicly funded organisations such as schools and hospitals. However local food organisations will work with local producers to a greater or lesser extent and so should be able be able to help point you in the direction of suitable farmers or growers and give you more information about what products are produced in your region.