Also known as celeriac, celery root is not the root of the stalk celery shoppers are used to seeing at the local grocery. While the taste is similar to celery, and the young and tender green top stalks and leaves may be eaten, it is the underground root that is the sought-after portion. Celery root may be mashed and used as a side dish, much like potatoes or in a pot of soup as a thickening, flavorful base. Home gardeners may easily grow a crop of celery root via a simple process.
Start seeds indoors 10 to 12 weeks before the last frost. Procure potting soil in a flat or the dried peat pot discs that plump up when soaked in water. Plant your celery roots seeds at a 1/8-inch depth as planting any deeper will not allow the sun and its warmth to reach the seed: Those two factors are important to help the seed germinate properly.
Cover the potted seeds with plastic wrap or the plastic dome that comes with planting kits. Keep soil moist but not drenched.
Place seedling tray in a warm area with temperatures from 70 to 75 degrees F until seedlings sprout. This should take about 2 to 3 weeks.
Thin the seedlings once they have germinated to one per disk or tray cell of your planting tray. Let the newly thinned seedlings grow indoors in temperatures averaging between 60 and 70 degrees F.
Pick a spot in your garden where you would like to plant your celery root. Allow about 6 to 8 inches between each anticipated plant: This will let you know the length of the row of garden soil space you will need. Celery root prefers full sun, organically rich, friable soil with pH ranges between 6.0 and 7.5. Soil test kits may be procured at the local garden center or your local agricultural extension may perform the test.
Create an indented row in your garden soil with your spade or hoe handle to the length of planting row you need. Follow this line as a guide and scoop away the dirt from the path in front of you. This creates a walk path, as well as allowing you to mound that extra dirt into a raised row that will receive your celery root transplants.
Transfer plants to the garden as early as two weeks before last frost. Being a cool weather crop, celery root can withstand mild frosts and in USDA Hardiness Zone 7 and farther south may be harvested in winter and spring from summer plantings. Mount soil slightly above the shoulders of the celery root base and water thoroughly to settle the transplants into their new home. Allow 1 to 2 inches of water per week during the growing season. In the hotter months, if the ground is dry when the tip of your finger is inserted into the dirt, increase watering until the ground remains moist to a depth of one inch.
Harvest in approximately 110 to 113 days depending on the variety. The celery root may be pulled up by the stalks. If soil is compacted around celery roots, carefully use a garden fork to assist while pulling upward on above ground plant. According to Cornell University's Horticultural Department, celery root will store well up to six months if kept in a cool cellar or in sand.