|Celery is a biennial generally grown as an annual. It requires deep, well drained soil with plenty of organic matter and a pH between 6.5 and 7.5.
Celery seed is notorious for slow germination, and if the ground is too warm, it may never come up at all. Aim for a soil temperature of about 70 Fahrenheit for best results, and plant indoors. Seeds require light to germinate.
When seedlings have 5 or 6 leaves, harden them off and transplant to their permanent growing site, about 4 inches deep. If your variety is not self-blanching, plant seedlings in a 1 foot deep trench, which gradually is filled in as the celery grows, preventing it from greening and becoming bitter.
Celery is a very thirsty plant, and must have a strong continuous supply of water. Mid-season fertilization will also help. Be on the lookout for slugs, and place beer traps if they become a problem. Incecticidal soap can discourage aphids.