I recently spent a couple of days touring several midcoast farms and markets with a group led by John Piotti, director of Maine Farmland Trust.

MFT is a statewide nonprofit with the mission of protecting Maine’s farmland and keeping farms working. The Trust, which has helped preserve more than 22,000 farm acres since its founding in 1999 and hopes to save 100,000 acres by 2014, uses a series of creative models designed to achieve its goal.

Nate Drummond and Gabrielle Gosselin of Six River Farm in Bowdoinham are young farmers who lease river bottom land on Merrymeeting Bay from George Christopher, a visionary farmer who has bequeathed his property to Maine Farmland Trust.

In the meantime, Christopher has transformed his holdings into a “farm incubator,” providing land, housing and other support to six startup farming operations. Six River grows about 7 acres of organic produce — more than two dozen types of vegetables — in rich alluvial soil overlooking the serene freshwater tidal estuaries.

We visited the wonderful Crystal Spring Farmers’ Market in Brunswick, where we lingered at the Six River tent and bought as much as we could carry — fat tomatoes, multicolored peppers, garlic, spring onions, squashes, potatoes and lovely blue-green Tuscan kale.

Spring Day Creamery’s award-winning handmade cheeses and the breads from Barak Olins’ Zu Bakery (especially his chewy sourdough miche) were just a couple of the market’s many other highlights.

The Crystal Spring market, on Pleasant Hill Road in Brunswick, is open 8:30 a.m. to 12:30 p.m. Saturdays through October.

PORTUGUESE POTATO AND KALE SOUP

Simple and straightforward, this delicious soup (“caldo verde” in Portuguese) uses the fall potato and kale harvest to great advantage. Serve it with Last-of-Summer Tomato Salad and slices of good, chewy bread.

Serves four.

2 tablespoons olive oil

½ pound garlicky sausage such as chourico, linguica or kielbasa, thinly sliced

1 large onion, chopped

4 cups chicken broth

1½ pounds potatoes (Yukon gold, red or all-purpose), thinly sliced (peeling optional)

1 medium bunch (about 1½ pounds) kale, thick stems removed and thinly sliced (see note)

Salt and freshly ground pepper to taste

In a large saucepan or soup pot, heat oil. Add sausage and onion and cook over medium heat, stirring occasionally, until sausage browns lightly and the onion softens, about 10 minutes.

Add broth, potatoes, kale and 2 cups of water. Bring to a boil over high heat, reduce heat to medium-low and simmer, partially covered, for about 30 minutes until potatoes are very soft (almost falling apart), and the kale is tender.

Use a large fork or whisk to break up some of the potatoes against the side of the pot to thicken the soup slightly. Adjust liquid, adding more liquid if necessary. Season with salt and pepper to taste.

NOTE: The best way to slice the kale is to roll several of the washed leaves up into a cylinder and use a sharp knife to cut crosswise into ½-inch ribbons.

LAST-OF-SEASON TOMATO SALAD

Green tomatoes plucked from the vine to escape potential frost and left to ripen on a window sill are still very much worth eating raw. Sarah Spring’s blue cheese from her Spring Day Creamery in Durham, which won second place in the 2011 American Cheese Society competition, would be a great choice if you can get it!

Serves four.

4 to 5 tomatoes, thickly sliced

1 cup thinly sliced red onion

¾ cup crumbled blue cheese

3 tablespoons chopped flat-leaf parsley

3 tablespoons olive oil

2 tablespoons balsamic vinegar

Salt and freshly ground black pepper

Shingle tomatoes on a large platter with the onion and sprinkle with salt and pepper. Scatter with cheese and parsley; drizzle oil and vinegar over before serving.

Brooke Dojny is author or co-author of more than a dozen cookbooks, most recently “The New England Clam Shack Cookbook” (Storey 2008).