The slight changes in color of the foliage will help determine the nitrogen needs and when sidedressing should be done. Irrigation - Successful production of celery requires continuous growth. To achieve this, irrigation immediately after transplanting is required. Frequent irrigation of 1 to 1.5 inches of water per week during the growing season is needed. Irrigation during the 6 weeks prior to harvest is especially important due to rapid plant growth.
Adequate irrigation can help prevent blackheart, a physiological disorder.
This disorder occurs when young leaves in the center of the plant do not get enough water and calcium to stay alive. The resulting dead tissue turns black and often decays. Insect Control - Major insect pests of celery include aphids, leafhoppers, carrot weevils, flea beetles, leafminers, armyworms and loopers. It is important to control leafhoppers, a common carrier of viruses. See the current N. C. Agricultural Chemicals Manual or your county extension agent for the latest recommendations.