Celery Dorato Gigante 2. 80-85 days. If you are used to Florida celery and have never eaten good Italian celery, you are in for a real taste treat. Start seedlings about 10-12 weeks before set out date (two weeks after last frost date). Sow 5-6 seeds/square inch and cover with 1/8th inch of soil mix. If possible, keep flat at 75° F. Celery is slow to germinate and will take 14-21 days to germinate. When seedlings are two inches tall, transplant to individual containers (a six pack works fine). Keep well watered. Transplant outside and space 6-8 inches. If using rows, space rows at 24 inches. Celery grows best in a fertile soil. If you want to blanch your celery, wait until three weeks or so before harvest. Blanch by covering the plant with paper or cardboard. 3 gram packet. Approximately 2000-2500 seeds per gram.