Osborne Quality Seeds recommends purchasing only enough pelleted seed for your current growing season. Conventional pellets are not NOP compliant.

Organic Celeriac Seed Growing Information
Apium graveolens
Transplant: Celeriac plants are slow growing, so start seeds 10-12 weeks before transplant date. Start in trays at 1/8” depth. Plant outside after last frost.
Spacing: 6-12” apart in rows 24” apart.
Growth needs: Grows best in fertile soil that is high in organic matter. Regular irrigation is crucial for optimal yield and quality. Bolting can occur if starts are exposed to temperatures below 55° F for more than 10 days.
Harvest: When bulbs are desired size for celeriac, which can be sold fresh with tops or bulk without tops. When stalks are of desired size for celery. Foliage can cause a rash, so wear long sleeves when harvesting on warm, sunny days.
Storage: Store celeriac for 6-8 months at 32° F.