Question: What is the best fertilizer for celery? How do you time the application? -Paul H.
Answer: Celery has a relatively small root system and it isn’t that great at getting the most out of the nutrients available, so it needs a little help from fertilizer to make the soil nutritious enough to support its growth. You’ll most likely need to fertilize before planting celery and then twice during the growing season to maximize your yields.
For general purposes, soil where celery will be grown should be treated with a complete fertilizer that is high in potassium, such as a 4-4-8 blend, before the celery is ever planted. Performing a soil test before planting celery is advised so you can follow the recommendations you receive along with your test results. If you decide to have a soil test, contact your local Extension office for information about how to proceed. If the test indicates that you should apply a fertilizer, mix it into the soil to a depth of six inches. If you use compost where you grow celery, apply a maximum of one inch of well rotted compost per 100 square feet of garden plot.
Once celery has been planted, side dressing with nitrogen helps to ensure a bumper crop. Apply ¼ cup of 21-0-0 nitrogen per each 10-foot row of celery as a side dressing at the fourth week after transplant and eighth week after transplant of celery’s growth season.