Twenty-six years ago, when Ruth and Bob Johnson of Johnson’s Farm in North Bend   first set up their booth at farmers markets, they sold mostly melons. People would glance at the produce and ask if they had chili peppers, but neither Ruth nor Bob had ever even eaten hot peppers much less grown any.

As the inquiries continued, the Johnsons started growing and selling hot peppers, although they weren’t entirely sure what to do with all that heat.

Over the years, the Johnsons have experimented with different chili peppers, and as customers snapped them up, Ruth and Bob asked for recipes. Consequently, they are not only sellers of their chili peppers but also contented consumers.

Members of the genus Capsicum, most peppers contain a chemical called capsaicin, which is responsible for the burning sensation most of us experience when eating them. The pith of the seeds and membranes in the peppers contain the highest concentration of capsaicin, but you’ll likely feel the burn when eating the flesh of the peppers.

In 1912, Wilbur Scoville developed a method to measure the heat of chili peppers. Peppers vary in their intensity from 0 Scoville units for bell peppers, which records no discernible level of heat, to more than 2,000,000 units for Trinidad Moruga Scorpion, which is considered the world’s hottest chili pepper. In comparison, the popular jalapeno measures between 3,500 and 8,000 Scoville units, and the habanero measures between 100,000 and 350,000 units.

Among the varieties the Johnsons grow are Anaheim, cherry bomb, habanero, Hungarian wax, jalapeno, Mexibell, pepperoncini, poblano, red cayenne and Serrano peppers.

Anaheim. This usually mellow pepper (500-1,500 Scoville units), also known as a California or Magdalena pepper, may be much hotter (4,000-5,000 units) if you grow seeds from the New Mexico variety. Ruth Johnson uses the Anaheim or poblano in her chili relleno recipe.

Cherry bomb. The lovely, bright red cherry bomb (2,500 to 5,000 Scoville units) holds some heat but stays crunchy when pickled. Johnson removes the seeds, stuffs the pepper with cream cheese and grills it.

Habanero. With a heat scale ranging between 100,000 and 350,000 Scoville units, this innocuous-looking orange pepper packs a heat punch. “This pepper is the hottest we grow and eat,” says Johnson. “Lots of people make it into salsa, but I usually make habanero jelly and spread it with cream cheese on toast.”

Hungarian wax. This yellow-green pepper is roughly as hot as a jalapeno (3,500-8,000 units). It’s frequently pickled or stuffed, and Johnson freezes it to use in casseroles, soups and stews in the winter. “Cut off the stems, remove the seeds, and cut into bite-sized pieces to freeze,” says Johnson. “The pepper will lose its crispness when you thaw and cook it, but it retains its spicy flavor.”

Jalapeno. This ubiquitous, deep-green pepper is commonly used in salsas or pickled. Jalapenos frequently make the appetizer section at restaurants in the form of cream-cheese stuffed poppers.

Mexibell. A cross between a bell pepper and a chili pepper, the mild Mexibell is more sweet than hot (100-500 units). This pepper gives a little kick to the classic stuffed peppers. Johnson stuffs her Mexibells with ground beef and rice and bakes them.

Pepperoncini. Pale yellowish-green and mild (100-900 Scoville units), this pepper is frequently pickled. Look for it on salad bars and in Greek salads.

Red cayenne. Also known as the Guinea spice or cow-horn pepper, this brilliant red pepper is moderately hot at 30,000-50,000 Scoville units and is ground, dried and sold as red or cayenne pepper. “Cayenne peppers are big sellers,” says Ruth Johnson. “Lots of people buy them and make vinegar-based hot sauces with them or dry them and grind them into homemade chili powder.”

Poblano. Mild-flavored (1,000-2,000 Scoville units) and gorgeous in its deep, rich, purplish-green color, the poblano is a fairly large pepper that’s perfect for stuffing. Dried or roasted poblanos are usually called ancho peppers. The Johnsons like this pepper stuffed and grilled or roasted.

Visit with the Johnsons at the Haymarket Farmers Market on Saturday, 8 a.m. to noon, and Old Cheney Road Farmers Market on Sunday, 10 a.m. to 2 p.m.