Ingredients that fetch top dollar in underground markets and garnish plates at fine-dining restaurants may — quite literally — grow like weeds in your front yard.

The new frontier among top restaurants is "field-to-table," a version of farm-to-table dining that elevates ingredients found in the wild, such as mushrooms, stinging nettle, dandelions, miner's lettuce, and huckleberries.

Some of the most highly rated restaurants in San Francisco, including Benu, Quince, Atelier Crenn, and Lazy Bear, hire professional foragers to supply them with the freshest ingredients that Mother Nature has to offer. These modern hunter-gatherers spend their days, rain or shine, picking food and plants in the wild and can earn upwards of $1,000 for a fruitful haul.

Business Insider spent the day with Bryan Jessop, a professional forager who gave up a career in economics to follow his passion, to see how he makes a living by walking in the woods.