Celery seed numbers approximately 960,000 per pound. It is advisable to 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.

Direct seeding is not recommended due to the difficulty in establishing a uniform stand and the long time needed to harvest. Direct seeding is possible where an excellent seedbed can be made and crusting prevented by solid set irrigation. Pelleted, vigorized seed and precision seeding should be used. Plug transplants are available from specialized transplant producers and should be used. 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 in. tall. Move plants to the field when seedlings are 4 to 5 in. tall and temperatures are above 55 F. Seedlings larger than 4 inches may show more bolting and be later maturing. For later crops, one may plant in open beds about May 1 and transplant to prepared fields in July. Clipping the leaves of the seedling 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.

It is advisable to go for machine transplant of seedlings to ensure a more uniform depth of planting, even growth. Never allow celery plant roots to dry out during handling and transplanting. Rows should be spaced 20 in. apart with plants spaced 6-8 in. 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 spacing will result in plants that are more open than desired.

A soil test is the most accurate guide to fertilizer requirements. The following recommendations are general guidelines that are applicable in the United States: Mineral soils: Add lime to maintain a pH above 6.0 on mineral soils. Transplant Seed-beds - Broadcast and rotate in a ready-mixed fertilizer such as 10-30-10 at 600 lb./acre. Fields - If available, apply manure at 10 tons/acre is spread and disked in during the spring months. Before transplanting, broadcast and disc in the following: Nitrogen: 150-200 (N) lb./acre. Apply remaining nitrogen as indicated below. Phosphate: 175-200 (P2 05) lb./acre Potash: 150-200 (K2 0) lb/acre Sulfur: 20-30 (S) lb/A Three weeks after transplanting side-dress with 35-70 lb./acre of nitrogen. Apply another side-dress as needed. When using calcium nitrate applied through irrigation, limit nitrogen applications to 25-30 lbs./acre at any one time or excessively fast growth will occur. This may result in cracking and related disorders. Fast growth will also result in celery that will become pithy quickly, reducing keeping qualities. If magnesium deficiency is likely to occur, apply Epsom salts at 5 to 10 lb./acre when the plants are about one-third grown. When boron is needed, broadcast boron at 1-2 lb./acre. A potassium excess or a boron - potassium imbalance can cause "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 lbs calcium chloride or 15 lbs calcium nitrate per acre. If moisture stress continues, reapply calcium chloride or calcium nitrate once per week. Muck soils: Add lime to maintain a pH above 5.5 on muck soils. Transplant Seed-beds - Broadcast and rotate in a ready-mixed fertilizer such as 10-30-10 at 600 lb./acre. Nitrogen: 100-150 (N) lb./acre. Apply additional nitrogen as indicated below. Phosphate: 175-200 (P2 05) lb./acre Potash: 150-200 (K2 0) lb/acre Sulphur: 20-30 (S) lb/A Three weeks after transplanting side-dress with 35-70 lb./acre of nitrogen. Apply another side-dress as needed. When using calcium nitrate applied through irrigation, limit nitrogen applications to 25-30 lbs./acre at any one time, or excessively fast growth will occur. This may result in cracking and related disorders. Fast growth will also result in celery that will become pithy quickly, reducing keeping qualities. If magnesium deficiency is likely to occur, apply Epsom salts at 20 lb./acre (2 lbs actual magnesium) when the plants are about one-third grown. If deficiency persists beyond 10 to 14 days, reapply 20 lbs Epsom salts per acre. Two applications should be sufficient. When boron is needed, broadcast 10 lbs of borax per acre ( 1 lb actual boron). A potassium excess or a boron - potassium imbalance can cause "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 lbs calcium chloride or 15 lbs calcium nitrate per acre. If moisture stress continues, reapply calcium chloride or calcium nitrate once per week.

Celery requires a uniform supply of water. Frequent irrigation is preferred. 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.

And Storage Celery may be hand harvested or machine harvested. Harvest when stalks are of sufficient size but before any pith has developed in the petioles. In some 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.

(Quoted from USDA Ag. Handbook): Celery should be stored at 32 F and 90-95% relative humidity. If stored in rooms, which hold uniformly at 32 F, celery should keep for 2 to 3 months. 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 hydro-cooling, 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 is used, fans should be located so that they will provide adequate air circulation. Celery should not be stacked more than four crated high in storage 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.

Celery is packaged in 55-65 lb. crates and wire bound crates, or flat pack containing 2 1/2 to 6 dozen bunches each. Celery hearts are packaged in 24-28 lb. cartons, holding 12 or 18 film bags, or 32-38 lb. wire bound cartons.