Start indoors 10 weeks before last frost. Scatter seeds on soil mix and lightly cover with 1⁄8 inches of soil, as light is needed for germination along with a soil temperature of 21 degrees C and constant moisture. Celery will take 7-14 days to germinate. When seedlings are about 1 inch tall, transplant to individual pots. Transplant after all risk of frost, spacing about 6-9 inches apart in rows 24-32 inches apart.
Full sun required. Celery is a heavy feeder and grows best in soil rich in organic matter with pH of 6.5. Before planting add plenty of compost and rotted manure. Celery has a shallow root system. To conserve moisture and cut back on weeds, mulch around the plants and water during dry spells. Lack of boron may cause stem cracking. Blanching is not necessary but it does improve flavour.
Young stalks on the outside of the plant can be harvested anytime. The entire plant is harvested once a desirable size is reached, remembering celery has a long maturity of 100-120 days. For best flavour and longer storage, water plants the day before harvest.
Pests & Diseases:
Aster Yellows which is caused by leaf hoppers can cause new growth to be distorted. Spray plants during the evening with an insecticidal soap or pyrethrum product.
Everything except carrot, parsley, dill and parsnip.