How to Grow Celeriac from a Seed

Soak the celeriac seeds in a bowl filled with water for 10 to 12 hours to soften their shells, aiding in germination. Remove the seeds and place them on a dry paper towel for two to three hours.

Fill a seed tray with seed starter mix until 1/4-inch below the edge. Plant an individual seed in each cell, 1/4-inch-deep in the growing medium. Alternatively, sow three to four seeds in a 4-inch plan pot filled with sterile potting soil. The best time to start the seeds indoors is eight to 10 weeks before the last expected frost date in your area.

Water the tray or pot lightly until excess water drains through the holes in the bottom. Discard excess water. Set the tray or pot in a sheltered spot with consistent temperature between 70 and 75 degrees Fahrenheit.

Inspect the tray or pot regularly and irrigate it lightly whenever needed, so the soil remains evenly moist at all times. Avoid dousing the tiny seeds with water, but provide a steady supply until excess flows out through the drainage holes. Seeds typically germinate in two to three weeks.

Set the tray or pot in a cooler indoor spot, preferably with consistent temperatures between 60 and 70 degrees Fahrenheit. Pull out weaker seedlings in the pot, leaving only one behind. Irrigate the pots regularly to maintain evenly moist soils.

Transplant the celeriac seedlings outdoors when they are 2 to 2 1/2 inches tall. Loosen the soil to a depth of 4 to 6 inches and incorporate shovelfuls of organic matter and starter fertilizer into it. Ensure the planting site receives full sunlight. Set the seedlings 6 to 8 inches apart, in rows 1 1/2 to 2 feet wide.