Fresno chile peppers (Fresno Red) are bright red, fresh peppers that are typically about 2 inches long and about 1 to 1/2" wide at the top, tapering down to a rounded end. The flavor profile is sweet and hot. The chile is thick-fleshed and waxy. They are easy to confuse with red jalapenos until you taste one. The jalapeno is narrower at the top and hotter than the jalapeno. There is also a green Fresno pepper, but the red is more commonly sold in stores, and it is sweeter than the green.
These chiles are hot, but not searingly so. On a relative heat scale of 1-10, they are about a 6.5, similar to the Holland chile. The Scoville rating is 2,500 – 10,000 units.
These are not chiles you'll commonly find in Mexico. They are cultivated in New Mexico. They are usually harvested in the fall, but they can be found in the U.S. year-round. See substitutes below.
Use these brightly colored peppers in fresh salsas, pickled, or even a fresh ceviche.
If you can't find Fresno peppers you can substitute equal amounts of one of these chiles:
Fresno chiles are easier to find in the West than they are in the East. Look for them in well-stocked grocery stores as well as many Mexican markets. You can also purchase them online at Amazon.com: Fresh Red Fresno Chile Peppers 1 lb.
You can store these chiles refrigerated, in a plastic bag, for about a week. Older chiles may develop soft spots as the start to decay, and the flavor diminishes as well.
These peppers, like many others, freeze very well. Simply slice them in half, lengthwise, then remove the stem, seeds, and membranes. Place the halves on a baking sheet that will fit in your freezer. Freeze the peppers until they are solid then place them in a zipper-bag suitable for freezing. Make sure to remove as much air from the bag as possible. The peppers should last at least 6 months.
Fresno chiles cut in half lengthwise.
These chiles are not challenging to grow, but they do want some hot summer daytime temperatures and prefer cool nights. You can purchase live plants in spring from Chileplants.com or try your local nursery. You can grow them from seed too, which you can find locally at a good plant nursery or from many seed sources online.
The plants grow to be from 18" to 24" tall, and it takes 60-70 days to harvest. If growing from seed, Eden Brothers suggest starting them indoors 8-10 weeks before your last anticipated frost date. The young plants can then be set out.
Here is a image of Fresno red chiles (far right). To the left of the Fresno chiles are green jalapenos and then red jalapenos. You can clearly see the shape and size for comparison.