A ristra is a string of dried chiles, garlic or other foodstuffs. But in New Mexico, when someone talks about a ristra, they're referring to the string of red chile pods that can be found hanging as decoration on many New Mexican homes, especially those made of adobe.
Ristras of chiles are sold at farmers' markets and are seasonally fresh in the late summer or early fall. Ristras are said to bring both good health and good luck.
Red chile ristras can be found throughout the Land of Enchantment as decoration. They're often hung on front porches and portals as a cheerful welcome. They can also be hung in kitchens, where the chiles can be used as needed.
The red chile pods of ristras were once green chile pods that were left on the vine long enough that they turned red. Then they were picked and strung with twine onto a ristra rope.
Chiles are part of the Capsicum genus in the nightshade family of plants. Other nightshades include tomatoes, eggplant, and potatoes. Chiles are a type of pepper. They are not related to black pepper, but they are related to other peppers, which can range from sweet bell peppers to jalapenos to spicy habaneros. The New Mexican chile, which is grown throughout the state but is most well known as coming from Hatch, is usually an Anaheim chile.
Chile is so important to the state of New Mexico that we have a state question: red or green, meaning, would you like red or green chile with your meal?
There is some controversy over how the word chile should be spelled. Some spell it chili, and others chile. In New Mexico, we spell it chile with an "e." Chile is the Hispanic spelling of the word.
There are many types of hot chile peppers. Here's a tutorial on some of the spiciest.