Kale gets better with frost, which causes it to turn sweeter.

And now this sweet, dark, leafy green, which some call a super food because it is packed with nutrients, will be available for sale this winter at Mermaid Farm and Dairy in Chilmark on Middle Road.

The farm grows two varieties of kale, oleracea and napus, for two different growing seasons. Oleracea is a curly variety bred in southern Europe, while napus is a hardy, flat-leafed variety better suited to withstanding winter temperatures.

The farm has about 6,000 square feet of kale, about half of which will stay in production through the use of hoop houses.

The abundance of kale at Mermaid Farm was celebrated last weekend at a kale festival, which included tours of the kale fields with their many shades of greens, and a variety of dishes prepared with kale. Two kale queens were named — Hara Dretaki for her kale greens pie and Jackee Foster for her kale salad with apple. Runners up were Jessica Roddy for her Mermaid Farm kale and feta pizza and Sara Andresen for her kale, beet and carrot salad.

Cathy Walthers, president of Slow Food Martha’s Vineyard, which sponsored the event, marveled at the quality of Mermaid Farm kale. “The kale here is the sweetest I’ve ever had,” she said while stirring a pot of kale and cabbage soup she had prepared as part of a cooking demonstration.“People don’t know what to do with kale sometimes because they think they don’t like it,” she said. “But it can be really good and it’s good for you.”

North Tabor Farm in Chilmark is also selling baby kale bagged and ready to go at their North Road farm stand and at Cronig’s Market.

In other farm news:

• Whippoorwill Farm will hold a winter vegetable pickup today and tomorrow at their Stoney Hill Road location in Oak Bluffs. Carrots, potatoes, lettuce, onions and broccoli will be available in every bag; cabbage, beets, Brussels sprouts and turnips may also be be offered. Pickup is from 9 a.m. to 1 p.m.

• On Dec. 17 the last winter farmers’ market of the season will be held at the Agricultural Hall in West Tisbury.