When you choose to support your local farmers by buying your produce, meat, dairy, snacks, and honey from the farmers market you are promoting sustainable practices in two main ways. When the spuds, carrots, cucumbers, peas, tomatoes are ready for picking, the farmer will simply pick them off into a basket. No stickers are needed to identify where they came from, cucumbers will not be shrink-wrapped, herbs will not be encased in a plastic prison. When you shop at your local farmers market you are promoting the use of fewer or no packaging, you can simply place the produce into your tote bag and take off.
Since the products at your local farmers market are coming from within 150 km (a two hour round trip drive), this means that your food will have a minimal carbon foot print of 0.03 tonnes of CO2 and uses 25 L of fuel. The food at your local supermarket most likely came from far away lands such as California. The carbon footprint of your food coming from California 2,833 km away is 1.96 tonnes of CO2 and 730 L of fuel. This represents a 6400% increase in CO2 emissions The numbers speak for themselves, our current global food sources are having a enormous impact. When you shop locally, you decrease CO2 emissions, pollutants, wear and tear on the roads. Local farmers have higher job security and with the surplus money they generate they spend the money on businesses that you may own or work at.
Why would you want to give someone that doesn't live in your area money? They don't live here, so why would they care about making it the best that it can be, they don't have to deal with the majority of the side effects when they do not have local interests.
Another benefit to having local farms is that if you ever feel to need to check for sustainable and humane farming practices, well guess what it is only 150 km. You could make a trip out to the farm, and check whether they are treating their animals humanely, or whether they are using an obscene amount of pesticides. If you are getting your food from California 2,800 km away it is difficult to get to know the farmers that are growing your food.