Celery Seeds,
D'Elne

Celery is best started indoors 8-10 weeks before the last frost date in your area. Transplant seedlings outdoors once the soil is at least 50 F and nighttime temperatures stay reliably above 55 F; celery is a biennial, and a couple of weeks of nights in the 40s will send year-one plants to seed instead of thickening their stalks. In warmer climates, celery can also be grown in the cool seasons of fall and winter. If you're not sure how to find your first and last frost dates, consult our blog post 'Our Experts Answer Questions, Share Resources.'

Starting seeds indoors: Sow seeds in seed trays or small pots filled with a seed-starting mix. Surface sow the tiny seeds, barely covering them and gently pressing them into the soil. Keep the soil moist and maintain a temperature around 70-75 F until germination.

Transplanting: Harden off seedlings by gradually exposing them to outdoor conditions for about a week. Transplant when seedlings have 3-4 true leaves. Space plants about 10 inches apart in rows 2-3 feet apart.

Incorporate plenty of organic matter, such as compost or aged manure, in the soil to enhance soil fertility​. Water deeply and regularly, ensuring the soil remains moist but not waterlogged. Mulch around the plants to retain soil moisture and regulate temperature. Apply a balanced, slow-release fertilizer at planting and side-dress with additional fertilizer every 4-6 weeks. Avoid high-nitrogen fertilizers to prevent excessive leafy growth at the expense of stalk development​.

• Celery and celeriac are insect pollinated and should be isolated by 1 mile from each other to ensure seed purity.
• Both plants are biennial and must either be dug and stored or be left in the ground to overwinter and flower the following spring.
• Harvest the flowers and collect the seeds when they have completely dried on the plant.
• When stored properly, celery and celeriac seeds will last for 5 years or more.