Early: Utah 52-70-R Improved.
Late: Florida 683. For trial: Clean Cut, Tall Green Light, Ventura.
Processing: Processor specifies varieties. Tall varieties are preferred. Some that have been used include: Tall Utah 52-75, Tall Utah 52-70R Improved, T.U. 52-70HK, Matador, Picador.

Others for trial: Clean Cut, Conquistador, Green Giant, Promise, Tall Green Light, UC8-1, UC10-1, UC26-1, Ventura, Vicar, VTR-1325, VTR-1744, VTR-1901, VTR-1917, XP-85.

Note: The following varieties are reported to have Fusarium resistance: Picador, Matador, XP-85, Vicar, Deacon (tall), Promise, UC8-1, UC10-1, and UC26-1. Fusarium is a soilborne fungus now limiting celery production in certain areas in California. It is spread in all ways that soil or water are spread between production areas or fields, through transplants, plant residue, and soil. Once the disease is established, the field is contaminated indefinitely.

Novelty: Pink Celery and Solid Red (pink and red stalked, respectively)

Other species provide types for other uses. Apium secalinum leaves are used for garnish, flavoring and medicinal uses while celeriac (Apium rapaceum) produces an enlarged root-stem which is a popular vegetable in Europe and in specialty markets.

SOIL

Muck soils are ideal because of their high moisture-holding capacity. A pH of 5.2-6.5 is required for good production. Fertile, well drained mineral soils are also suitable where sufficient water can be provided throughout the growing season. Sandy soils are not recommended.

SEED AND SEED TREATMENT

Celery seed numbers approximately 960,000 per pound. Use only treated seed for transplant production. Celery is not commonly direct seeded. Some companies provide vigorized or primed seed that germinates uniformly and rapidly. Use only highest quality sized and density graded seed.

SEEDING AND TRANSPLANT PRODUCTION

Direct seeding is not recommended due to the difficulty in establishing a uniform stand and the long time needed to harvest. Pelleted, vigorized seed and precision seeding should be used for transplant production.

Plug transplants are available from specialized transplant producers when prearranged by contract. For production of on-farm greenhouse transplants, broadcast seed into a suitable soil mix or sterilized soil, transplant to other flats when seedlings are 1 to 2 inches tall. Move plants to the field when seedlings are 4 to 5 inches tall and temperatures are above 55 F. Larger transplants are more susceptible to bolting and to transplant shock, and are later maturing. Clipping the leaves of the seedlings results in greater uniformity, stronger stems, and allows more light to reach the slower-growing smaller seedlings.

In field or greenhouse transplant production, care must be exercised to protect plants from mean daily temperatures below 55 F for extended periods of time (10-14 days), and particularly below 45 F for even short periods. Such exposure preconditions celery to bolting and may result in severe losses in yield and quality. Varieties differ in susceptibility to bolting.

TRANSPLANTING

Celery is usually planted into the field after May 20, with most transplanting occurring in June. Celery planted in the field around June 1 will be ready to harvest about October 1.

Dip celery plant roots in a solution made up of 3 lb 11-48-0 or 11-55-0 that has been dissolved in a 55-gal drum of water, or use such a starter solution in the transplanter water. Machine-transplant seedlings carefully to ensure a more uniform depth of planting and even growth. Never allow celery plant roots to dry out during handling and transplanting. Clip tops of transplants, if excessive, to reduce transplant shock. Planting before May 20 may result in excessive bolting unless plants are protected by row tunnels or field covers.

Rows should be spaced 15-20 inches apart with plants spaced 6-8 inches apart within the rows. If paired rows are used, use 12-14 inches between pairs of rows and space pairs 40 inches center-to-center. Using excessive spacings will result in plants that are more open than desired.

FERTILIZER

A soil test is the most accurate guide to fertilizer requirements. The following recommendations are general guidelines for Western Oregon:

Add lime to maintain pH above 5.5 on muck soils and above 6.0 on mineral soils.

Before transplanting, broadcast and incorporate the following on both mineral and muck soils unless otherwise specified:

Nitrogen: 100-150 lb N/acre. Apply remaining N as indicated below. For muck soils, reduce N rate by 40-50 lb/acre.
Phosphate: 175-200 (P205) lb/acre
Potash: 150-200 (K20) lb/acre. Excessive potash may aggravate boron deficiency problems.
Sulfur: 20-30 (S) lb/A
Magnesium: Apply 0.5-1.0 lb Mg/acre (5-10 lb Epsom Salts). For muck soils, apply 2 lb Mg/acre (20 lb Epsom Salts).
Boron: 1-2 lb B/acre. See also below.

Sidedress fertilizer: Three to 4 weeks after transplanting, apply 35-70 lb N/acre. Limit subsequent N applications to 25-30 lb/acre each, for a total of 200 lb N/acre. Individual applications should not exceed the rates specified since excess N at any one time may result in cracking of the basal portion of the petioles, celery that becomes quickly pithy, and has reduced keeping qualities. If magnesium deficiency is observed, apply Epsom Salts at 5 to 10 lb/acre. If symptoms persist beyond 10-14 days, a second similar application may be needed. Two applications should suffice.

If transverse cracking is noted, apply a boron foliar spray of 0.5 -1.0 lb B/acre. A potassium excess can cause a potassium-boron imbalance, which may also result in transverse cracking and "brown checking".

A calcium imbalance or deficiency can cause black heart. This occurs most frequently during periods of moisture stress and rapid growth during periods of high temperature. If temporary wilting occurs, irrigate, then spray (direct into the heart of the plant) with 10 lb calcium chloride or 15 lb calcium nitrate per acre. If moisture stress continues, reapply calcium chloride or calcium nitrate once per week until the stress period is over.

IRRIGATION

Celery requires a uniform and regular supply of water. Frequent irrigations are preferred. Irregular or infrequent water applications may aggravate black heart (see also comments for calcium above). A total of 18-20 inches of water may be needed in western Oregon.

Soil type does not affect the amount of total water needed, but does dictate frequency of water application. Lighter soils need more frequent water applications, but less water applied per application.

Because celery is often harvested late into the fall when frost can occur, irrigation for frost protection should be considered. Solid-set irrigation for late plantings allows water applications during a frost event to prevent frost damage. This protects plant tissues from damage because of the heat released as water freezes on the plants. Apply water using smaller mist nozzles when possible, and continue applying water after the frost event is over until all ice is melted from the plants.

Using standard irrigation nozzles in frost protection is also helpful, but may create difficulty in harvest from wet field conditions. Irrigating fields just before a frost event can be helpful, even if water application can not be continued throughout the frost event, but this is not as effective as applying water throughout the frost event.

In Oregon, drip irrigation is used in celery grown for processing to reduce risk from foliar diseases such as Septoria leaf spot for which there is little practical control. Drip lines, lay-flat plastic pipe, and other hardware are installed after transplanting, when celery is about 8-10 inches tall. The equipment is removed and stored after harvest for use on other crops.

GROWTH REGULATORS

Gibberellic acid (GA) has a label for use on celery to hasten maturity, to increase plant height, to increase yield, and to overcome stress due to cold weather or saline soils. Check a current label for rates and restrictions. Applications must not be earlier than four weeks before harvest as earlier applications may cause seed stalk formation (bolting). Caution: Use of GA on celery in the Pacific Northwest is suggested for trial only. We lack experience with this use under our climatic conditions.

HARVESTING, HANDLING, AND STORAGE

The University of California-Davis has a file on Minimal Processing of Fresh Vegetables that discusses film wrapping and other topics.

Average yields of celery for fresh market are reported as approximately 535 cwt/acre while good yields are about 700 cwt/acre. Yields of celery for processing are about 35 tons/acre. Celeriac yields are approximately 200 cwt/acre.

Celery may be hand harvested or machine harvested, but that which is grown in Oregon is hand harvested. Harvest when stalks are of sufficient size but before any pith has developed in the petioles. In some U.S. production areas, celery is trimmed to produce "hearts" which are packaged 2 or 3 per package with the stalks that are trimmed off being used for processing. It is critical that harvested stalks be quickly cooled.

STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)

Store celery at 32 F and 90-95% relative humidity. Celery should keep for 2 to 3 months if stored in rooms held uniformly at 32 F. However, less celery is stored now than in former years. Since wilting is a major cause of deterioration, it is best to store celery at very high relative humidity (98 to 100 %) and with sufficient air circulation to keep temperatures at the top and bottom of the room as nearly equal as possible. Spreading burlap on the storage room floor and keeping it constantly wet is one method of maintaining a high relative humidity. The use of perforated polyethylene film crate or carton liners also provides an effective method of maintaining high relative humidity to minimize moisture loss. Prepackaging with shrink film sleeves or with open-top plastic bags also is a good way to retain moisture without the danger of accumulating carbon dioxide or depleting oxygen.

Celery can be precooled by refrigerated forced-air cooling, by hydrocooling, or by vacuum cooling. Hydrocooling is the most common precooling method, and temperatures should be brought at near to 32 F as possible. In practice, temperature reduction is often only to 40 to 45 F. Vacuum cooling is widely used for celery packed in corrugated cartons for long-distance shipment. Ice is often added to the crates to keep the celery near 32 F.

Air circulation can be maintained around crates by using dunnage strips between the crates and leaving air channels between rows. If wall or ceiling refrigerating coils are used, fans should be located so that they will provide adequate air circulation. Celery should not be stacked more than four crated high in storages without forced-air circulation; otherwise, there is danger of overheating due to heat of respiration.

For better storage, celery should be cut with a small piece of root attached and harvested before the outer stalks become pithy. 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 to 34 F.

Use of the jacketed-room system for cold storage has proven successful for celery in Canadian tests. Weight losses at 32 F averaged 1.25 %/month in jacketed storage as compared with 2.5 %/month in directly cooled rooms.

An atmosphere containing 3 % oxygen and 5 % carbon dioxide reduced decay and loss of green color in celery held at 32 F in high-humidity storage.

PACKAGING

Celery is packaged in 55 to 65-lb cartons 2.5 to 6 dozen bunches each. Celery hearts are packaged in 24 to 28-lb cartons, holding 12 or 18 film bags.