Developed in the 1950’s, they say only one head fills a salad bowl. I counter that we don’t know the size of your salad bowl so we cannot be making any guarantees. But these big ruffled fluffled crumpled leaves make very large heads of a bright green color that are really tender and delicious. Withstands some heat, does well in cold too. Covered in a hoophouse it can withstand temperatures of 20° F! Good for baby greens, or mature heads in only 50 days.