Family: Umbelliferae
Genus and Species: Apium graveolens
Climate
Celery requires a long growing season and does not grow well in hot, dry summer weather. Celery prefers cool, but not cold, growing conditions.
Soil
Muck soils are ideal for growing celery because of their high moisture-holding capacity. A pH of 5.2-6.5 is required for good celery production. Fertile, well-drained mineral soils are also suitable where sufficient water can be provided throughout the growing season. Sandy soils are not recommended.
Spacing
Celery requires a bit tighter spacing than you might expect. Celery plants should be 6"-8" apart within rows spaced 15"-20" apart. If wider spacing is used the celery plants will open up more than is desirable plus make it difficult to control blanching.
Paired rows should be 12"-14" between each row of the pair with 40" center-to-center between the paired rows.
Direct Seeding
Direct seeding is not normally practiced.
Seeding For Transplants
Sow celery seeds at about 6 seeds per inch in a suitable soil mix or sterilized soil at 1/8" deep.
Alternate method is to broadcast celery seed into flats and transplant to other flats when seedlings are 1"-2" tall.
Care must be exercised to protect celery plants from average daily temperatures of 55°F and below for extended periods of time (10-14 days), and particularly below 45°F for even short periods. These temperatures will precondition celery to bolting and may result in severe losses in yield and quality. Celery varieties differ in susceptibility to bolting.
Germination
These seeds germinate best in soils around 70°F -75°F.
Germination will take 10-14 days.
Transplanting Into the Garden
Move celery plants to the field when seedlings are 4"-5" tall (6-8 weeks) and temperatures are above 55°F. Height is important for celery transplants as the larger transplants are more susceptible to bolting, transplant shock, and will mature later. Clipping the leaves of the celery seedlings will result in greater uniformity, stronger stems, and allows more light to reach the smaller seedlings.
Watering
To say celery is fussy about water is an understatement. Celery requires a uniform and regular supply of water. Celery also prefers frequent irrigations. Irregular or infrequent water applications may aggravate black heart as well as produce bitter or underdeveloped stalks.
Celery is often irrigated by drip irrigation to reduce risk from foliar diseases such as Septoria leaf spot for which there is little practical control.
Harvesting
Cut the celery plant off at just below the soil line. You can also cut individual stalks as needed but remember to replace the soil or mulch used for blanching.
Post-Harvest Handling
Celery should be hydro cooled as soon as it is harvested. Hydro cooling is the process of spraying or immersing vegetables in chilled water. Celery is often trimmed to produce "hearts" but this is not necessary.
Storage
Celery should be stored at 32°F and 90%-95% relative humidity. Celery should keep for 2 to 3 months in these conditions. Wilting is a major cause of deterioration.
To improve longevity, celery should be harvested before the outer stalks become pithy and with a small piece of root attached.
Some growth takes place in celery while in storage; the central stalks lengthen considerably.
Some blanching of the stalks also takes place in most cultivars during storage.
Celery is rather perishable, and under unsuitable storage conditions it is especially subject to watery soft rot. This disease originates in the field and is caused by a fungus that is able to develop to some extent even at 32°F-34°F.
Do not store celery with fruits and vegetables that produce ethylene gas.
Diseases
Black Heart, Early Blight, Late Blight, Aphids, Nematodes, Viruses and Septoria leaf spot
Pests
Aphids and Earwigs
Comments
Gently pull weeds up, as celery does not compete well with weeds.
To blanch celery, gradually pile soil or mulch up around the plants as they grow keeping the leaves exposed.
Celery leaves are great for flavoring soups and stews.
References
Oregon State University, "Celery, Commercial Vegetable Production Guide", Last modified 2002-12-27, Oregon State University, http://oregonstate.edu/Dept/NWREC/celery.html, Accessed 2003-01-04.
Bradley, F. M. and Ellis, B. W.(Ed.). (1992), Rodale's All-New Encyclopedia of Organic Gardening: The Indispensable Resource for Every Gardener, Emmaus, Pennsylvania: Rodale Press.