I purchased these seeds about 4 years ago and have been growing them from saved seeds ever since. They can withstand a cold winter better than Golden Self-Blanching or Utah Tall. I am in Zone 6b which is lower Middle Tennessee. It is not unusual to brush the snow off and see them growing undamaged underneath. I start the seeds in the spring and they will last through the winter then go to seed in the following summer. They also multiply and grow wider. Last fall I took them and divided them with friends. I replanted them in late September and they lived. I don't recommend doing that but I wanted my friends to see how well they grow during the winter. My soil is not great. I have never bothered fertilizing and they still did fine. After they are established, I don't bother watering unless there is a drought. The stalks are pencil thin and are best used in soups, salads, stir-fry or juicing. Flavor is stronger than store bought celery. It surprises people when they first taste it. I highly recommend for winter gardens.