42 days. If there was ever a kohlrabi variety to take this unusual vegetable out of relative obscurity, it’s Konan. Its AAS award-winning, pristine, icy-green globes and sweet, crunchy, alabaster flesh will make you stand up and take notice. Sturdy, uniform, healthy plants produce smooth-skinned bulbs that can reach up to 6 inches across for lots of delectable, cool-season dishes.