To grow the biggest celery plants, start with well-drained, sandy soil that is slightly acidic. Temperatures between 55-65 degrees are best with full sun or partial shade, and the plants need 1-2 inches of water a week. Water the soil deeply and frequently using a hose, a watering can or drip irrigation. After the plants reach about six inches in height, add mulch for moisture retention and temperature stabilization, especially in warm and dry climates.

Common pests to look out for include carrot rust flies, aphids, earwigs, slugs and flea beetles. Using row covers for the first 4-6 weeks of in-ground growing will help ward off pests during this pivotal developmental stage. Keep the ground area clean so it doesn’t attract diseases like powdery mildew or blight.

Celery has a long growing season and can take up to three weeks to germinate, so start seeding 10-12 weeks before the final spring frost for the longest harvest season. Soak the seeds in water overnight to help remove the natural germination inhibitors. Then sow seeds closely together on the surface of a high-quality seed starting mix in seed flats, trays or pots. Keep the soil moist and temperatures between 65-75 degrees.

Once the seedlings sprout, they need 16 hours a day of bright light, making LED or fluorescent grow lights necessary. After they develop true leaves, thin the seedlings to about two inches apart or transplant some to separate containers.

Seedlings are ready to transplant when they have 3-4 mature leaves and established roots. Wait until soil temperatures remain above 50 degrees at night and the threat of frost has passed. You should harden the seedlings for about a week before transplanting by exposing them to outdoor conditions for two hours a day. Container growing is a great option to save space or if you can’t have a traditional garden. Get a container at least three gallons in size per plant with good drainage; consider plastic containers for more moisture retention.

Celery requires a lot of nutrients but doesn’t forage well because of its shallow root system, so regular feeding is a must. Add organic matter like compost or manure during the initial planting or transplant, then fertilize once a month with a potassium-rich formula. You might also “side dress” with a high-nitrogen fertilizer to encourage growth. Test the soil at the start of the growing season and then periodically throughout to determine exact needs.

Celery can be grown as a biennial plant, producing stalks in year one and seeds in year two. However, most celery varieties can’t endure temperatures below 36 degrees. Mulch, row covers and frost blankets will help against the cold. Water the plant less often and add stakes to prevent drooping.

The pruning needs of a celery plant are minimal. Removed damaged or diseased leaves as needed along with any flowering stalks. This will let the plant direct its resources elsewhere.

Celery stalks are ready to harvest when they reach 6-8 inches tall. Focus on the mature outer stalks and cut them at the base to encourage continuous growth. Homegrown celery will be smaller and have a darker color than the celery at a grocery store.