Celery can be grown in all the states of the United States except Alaska and Hawaii, according to the Old Farmer's Almanac. Because extreme heat and extreme cold prohibit the growth of this long-season crop, these states are excluded. Celery is grown in USDA growing zones 2 though 10; however, planting time varies considerably based on the location it is being grown.
According to the Old Farmer's Almanac, celery requires cool temperatures, constant moisture and fertile soil to thrive. In the northern United States, celery is considered a summer crop, while in the southern United States, it is considered a winter crop. The difference in growing season allows for the year-round commercial production of celery in the United States.
Celery can be started indoors eight to ten weeks before the last frost. If planting celery for a winter harvest, late summer sowing is recommended as long as daily temperatures range between 55 and 70 degrees Fahrenheit. Soak seeds in water overnight to reduce germination times, and supplement the soil with organic fertilizer or compost before planting. Celery requires a lot of water to develop thick, solid stalks so be sure to water generously, especially during hot, dry weather. Fertilize celery regularly, and add mulch around its base to prevent it from drying out.