£* 1 "K, **«hS*Q Division of Agricultural Sciences UNIVERSITY OF CALIFORNIA HELD PACKING CELERY in crates, Salinas Valley, utilizing field lidding device Celery Production in California WILLIAM L. SIMS • JAMES E. WELCH • THOMAS M. LITTLE CALIFORNIA AGRICULTURAL Experiment Station Extension Service CIRCULAR 522 April, 1963 Distribution of the aver- age yearly celery acreage harvested in 1959 and 1960 in the principal producing counties of California. \ DELTA Harvest season? late fall SANTA CRUZ MONTEREY CENTRAL COAST Harvest seasons: early summer, late fall When production of celery for medicinal purposes was begun in Europe in the 16th century it was still a primitive plant, al- though it had been known for many cen- turies in the Mediterranean area where it probably originated. Cultivation of the plant for food was first recorded in France in 1623; by the early part of the 18th century there had been improve- ment of the wild type of celery previously transported to Italy, France, and Eng- land, and as early as 1726 the plant was being used in England to flavor soups and stews. Today, the acreage devoted to celery in the United States alone varies from 32,000 to 37,000 acres, approximately, and the value of the national crop ranged from $45,350,000 in 1961 to $49,781,000 in 1960. California's celery harvest was worth $26,302,000 in 1961—58 per cent of the nation s total for that year, on a cash-value basis. Celery ranked fifth in value among California vegetables in 1961, with 14,900 acres planted to it. the authors: William L. Sims is Associate Agriculturist, Agricultural Extension Service, Davis; James E. Welch is Associate Olericul- turist in the Experiment Station, Davis; Thomas M. Little is Agriculturist, Agricul- tural Extension Service, Riverside. SOUTH COAST Harvest seasons: winter, spring, late fall Celery Production in California h WILLIAM L. SIMS • JAMES E. WELCH • THOMAS M. LITTLE * The Plant i. A brief description of celery s growth habits. Celery (Apium graveolens L. var. dulce Pers.) is normally a biennial, al- though under certain conditions it de- velops as an annual. In the course of its \~, usual cycle a well-developed root system, a short, fleshy crown stem, and a rosette of leaves are produced the first year. The thick, fleshy petioles, or leaf stalks, of the rosette leaves comprise the principal f edible portion of the plant. Commercial handlers of celery usually refer to petioles as "ribs," "shanks," or "stems," and to whole marketable plants as "stalks" or "heads." During its second year the main stem, or seedstalk, elongates and branches to produce a shrubby plant about 3 or more feet in height. The plant bears com- r pound clusters of small white flowers, which produce flattened, dry fruits to- ward the end of the flowering season. Occasionally, celery plants develop as annuals and produce seedstalks the first season. Growers call this condition "pre- mature seeding" or "bolting," and af- fected plants are unmarketable unless seedstalk elongation is slow and occurs when plants have almost reached harvest stage. Single plants which show seedstalk elongation are often referred to as "seed- ers." Exposure of plants to relatively low temperatures is the main factor in bolting. Celery produces a well-developed root system (consisting of a tap root and later- als) when the crop is grown from seed to market maturity without transplanting. When transplanting is practiced, the tap root is destroyed and the fibrous system is comprised of a large number of adven- titious roots growing from the base of the plant. A large part of the root system occupies the upper 6 inches of soil — many of the roots are within 2 or 3 inches of the surface, but some penetrate to a depth of 2 feet or more. [3] Climate and Soil Celery is a cool-season crop re- quiring precise climatic conditions and a long growing season. Ideal conditions for commercial celery production include a relatively cool grow- ing season, a well-drained soil, and an abundant, uniform supply of soil mois- ture. The plants will tolerate considerable heat after they are established in the field, but during the last month or so preceding harvest temperatures should average no more than 60° to 70°F. Celery is dam- aged near the market stage by freezing temperatures. BOLTING, OR PREMATURE SEEDING This is a potential problem in spring- maturing California celery crops, espe- cially in those harvested from about mid- April to mid-May, and is sometimes a problem in winter-maturing crops har- vested after March 15 (approximately) . Bolting can also cause losses in late June in the first fields harvested during the early summer season. Exposure to relatively low temperatures (approxi- mately 40° to 55°F) for as little as 10 days or so near the lower temperature results in bolting when the plants are subsequently grown under favorable con- ditions. For this reason greenhouse celery plant growers maintain minimum tem- peratures above 60°F. Different celery varieties have different susceptibilities to bolting. SOILS Peat, muck, and loam soils are pre- ferred for celery culture, and heavy clays are not recommended. Celery soils should be well-drained. Because celery produces 60 tons or more of fibrous material per acre, soil moisture and nutrients should always be available in sufficient amounts. The addition of organic matter to min- eral soils improves both soil structure and evenness of supply of moisture and nu- trients. Nitrogen in large amounts is needed, particularly when the crop ap- proaches market maturity, and environ- mental conditions producing uniform growth should be provided. New celery growers should consult their local Farm Advisors about production problems. Varieties and Varietal Problems Varieties must suit season and district. VARIETIES Celery varieties grown in the United States belong to the golden, or yellow, class or to the green class. Commercial celery acreages in California are com- prised exclusively of green varieties, of which several varietal groups, or types, are available. Types grown in California, and principal varieties grown commer- cially in each of these types, are listed below. Summer Pascal type: Pascal 259-19 Green D5 Utah type: Ordinary Utah subtype: Utah 16-11 Tall Utah 10-B Delmar Crystal Jumbo subtype: Tall Utah 52-70 Tall Utah 52-70 H Compak No. 2 Slow Bolting type: Slow Bolting Green No. 12 Slow Bolting Green No. 96 Utah type and, especially, Crystal Jumbo subtype varieties predominate in California celery fields. Buyers prefer these varieties to Slow Bolting and Sum- mer Pascal types mainly because the trimmed heads are cylindrical, compact, and have attractive, well-overlapped ("shingled") petioles, a relatively large number of petioles, and good heart de- velopment. The leaflets of Ordinary Utah subtype varieties are slightly yellowish green and the leaflets of Crystal Jumbo subtype varieties are very dark, blackish green. Slow Bolting type varieties are 4 [4] Bolting reduces the crop's value THE CELERY PLANTS ABOVE were taken from two fields in the same area and were cut in half to show the effects of bolting. The plant on the left was taken from a field planted late enough in the season to avoid frost and is developing normally. The center and right-hand plants were subjected to an unseasonal cold spell and have started to develop seed stalks that will reduce their value for fresh market sale. [5 Table 1. Celery Harvest Seasons, Areas or Districts, and Varieties Grown, Principal Counties, and Average Yearly Acreage Harvested in 1959-60 Acreage has increased in last 10 years. t Acreage has decreased in last 10 years. % Counties with 50 acres or less. S Average percentages of the total acreage grown for 1959-60 were: winter, 26; spring, 18; early summer, 13 || Salinas Watsonvillc district. SI \SON AREA, AND VARIETIES GROWN COUNTIES ACREAGE Orange* San Diegot 1 590 varieties: 1,325 Tall Utah 52-70 Ventura* 1,050 Tall Utah 52-70 H Los Angelest 615 and some Other countiest 70 Utah 16-11 TOTAL 4,650§ Spring South Coast Orange 1,300 varieties : Ventura 975 Tall Utah 52-70 Los Angeles 945 Tall Utah 52-70 H Other counties 30 and some Slow Bolting Green No. 12 Slow Bolting Green No. 96 TOTAL 3,250§ Early summer Central Coast Monterey* 1,130 varieties: San Luis Obispo 730 Tall Utah 52-70 Santa Barbara 255 and some Santa Clara 220 Slow Bolting Green No. 12 Santa Cruz 70 Slow Bolting Green No. 96 Other counties 45 Pascal 259-1911 TOTAL 2,450§ Late fall Central Coast Monterey 3,510 Santa Barbara 1.965 San Luis Obispo 680 Santa Cruz 170 Santa Clara 125 Delta San Joaquint 995 South Coast Orange 125 varieties : Los Angeles 100 Tall Utah 52-70 Other counties 130 and some Tall Utah 10-B TOTAL 7,800§ STATE TOTAL 18,150 harvest during each and late fall, 43. if the harvesting seasons grown only when bolting might cause losses in Utah type varieties. Tall Utah 52-70 and Tall Utah 52-70 H are more attractive than Slow Bolting Green No. 12 and Slow Bolting Green No. 96, and therefore bring higher prices. Because of this, growers tend to arrange their plant- ings so that they can start harvesting the [6 Table 2. Usual Celery Planting and Harvesting Dates for Different Harvest Seasons PLANTING DATES HARVEST DATES SEASON BEGIN MOST ACTIVE END Winter* Springt Early summerj Late fall§ Aug.-Nov. Nov.-Mar. Mar-May J une- Aug. Nov. 20 Apr. 1 June 20 Sept. 1 Jan.-Mar. May-June July-Aug. Nov.-Dec. Mar. 31 July 31 Aug. 31 Jan. 15 * Crop produced almost entirely in the Los Angeles-Orange County (Los Angeles and Orange counties), Chula Vista (San Diego County), and Oxnard (Ventura County) districts of the South Coast area. t Crop produced almost entirely in the Los Angeles-Orange County and Oxnard districts of the South Coast area. J Crop produced almost entirely in the Salinas-Watsonville (Monterey and Santa Cruz counties), Santa Maria-Oceano (Santa Barbara and San Luis Obispo coimties), and Centerville-San Jose (Santa Clara County portion) districts of the Central Coast area. § Crop produced almost entirely in the Salinas-Watsonville, Santa Maria-Oceano, and Centerville-San Jose (Santa Clara County portion) districts of the Central Coast area; the Delta (San Joaquin County por- tion) district of the Central region; and the Los Angeles-Orange County district of the South Coast area. above two Tall Utah varieties as early as possible, and some growers plant them exclusively, gambling that weather con- ditions which cause bolting will not occur. Summer Pascal type varieties comprise only a small percentage of the California crop. Green D5, Delmar, Compak No. 2, and Slow Bolting Green No. 96 were in- troduced subsequent to 1957 ; the acreage planted to these varieties is small, and trial plantings by growers over a period of years will determine which ones will find a place in California. • Buyers, shippers, and crop reporters usually refer to all varieties of green celery as "Pascal." When Pascal is used in the horticultural sense, however, it re- fers to a specific varietal type and not to all varieties of green celery. VARIETAL PROBLEMS The susceptibility of the Utah type va- rieties to bolting under certain conditions, and the susceptibility of all varieties to late blight, a disease caused by the fungus Septoria apiicola, are perhaps the two most serious varietal problems in Califor- nia. Pithiness, a physiological disorder, often develops in the outer petioles of the popular Tall Utah 52-70 variety when the plants reach market maturity. In order to avoid losses from the spread of pithiness to inner petioles, harvesting usually must not be deferred. Thus, cut- ting of crops maturing during weak mar- ket periods cannot be postponed in antic- ipation of improved market conditions which might occur even a few days later. Cultural Operations Soil must be thoroughly prepared, both for direct seeding and trans- planting. PREPARING THE SOIL Most of California's celery acreage is on heavier soils and cultural prac- tices often vary from district to district. Fields may be disked, subsoiled, plowed, harrowed, and land planed — land plan- ing is important for uniform furrow irri- gation. After land planing, a soil treat- ment of aero cyanamid (800 to 1000 pounds per acre) is sometimes made to control pink rot (Sclerotinia scleroti- orum), and heavy applications of animal manure are often made at this time also. (See "fertilization," page 14.) After soil treatment and fertilization, the land is sometimes disked, chiseled, and then harrowed again. Before plant- ing, the field is furrowed or "listed" to make ridges for planting and furrows for irrigating; lister ridges may then be [7] Because chemical control measures and details on application rates may vary as new information is developed, the grower should refer to the annual "Vegetable Crop Pest Control Guide" put out by the University of California Agricultural Ex- tension Service. See your Farm Advisor for a copy. rolled with a smooth roller to make a firm bed — in some areas the beds are shaped with a spike harrow. Furrows may be spaced 24 to 40 inches apart, depend- ing upon whether single or double plant- ing rows are used and upon type of equip- ment involved. PLANTING Slightly over half of California-pro- duced celery is grown from transplants, and the rest is direct-seeded. Methods of planting vary from district to district, with the Salinas-Watsonville and the Santa Maria districts being predomi- nantly direct-seeded. Growing transplants in the greenhouse. About 60 to 75 days are required to pro- duce suitable transplants from seed. While transplants can be purchased from greenhouse operators, some producers of celery grow their own plants in order to help minimize production costs and to insure a supply of high quality plants. Greenhouse plants are seeded in wooden flats measuring 16 x 16 x 2% inches which are generally filled with a composted soil-mix or a U C light soil- mix. University of California Soils Mix B with fertilizer is recommended. This is a mixture of 75 per cent fine sand, 25 per cent peat moss, and fertilizer, which can be sterilized with steam or methyl bromide. Fertilizer can be added to each cubic yard of sand and peat moss mixture as follows: 6 ounces potassium nitrate, 4 ounces potassium sulfate, 2% pounds single superphosphate, 4% pounds dolo- mite lime, l 1 /^ pounds calcium carbonate lime, and l 1 /^ pounds gypsum. This mix- ture contains moderate amounts of avail- able nitrogen, but will require supple- mental feeding within a short time. It is not composted, and may be used the day it is made. Soil in flats is firmed, espe- cially at sides (methyl bromide or steam sterilization of filled flats may be neces- sary to prevent damping-off) . Seed is sprinkled over soil at the rate of 1 ounce to 15 flats. Seed is then covered lightly with sterilized sand and flats are watered and covered with steam or methyl bro- mide sterilized burlap or coarse sand. Infected celery seed may carry spores of late blight (Septoria apiicola) which may be the principal source of field infection. The spores can be killed by soaking seeds in a mesh bag for 30 minutes in water at 118°F — care should be taken to prevent the temperature from rising above 120°F, as high temperature will markedly re- duce seed germination. • In 20 to 30 days the plants should be about 1 to 2 inches tall, and they are then transplanted to other flats at the rate of 100 to 110 plants per flat. In about 30 to 40 days they will be large enough for transplanting into the field. • Before transplanting into the field, young plants are hardened by withhold- ing moisture, and by placing them out- side the greenhouse. Plants should not be exposed to temperatures below 55°F, as doing so may initiate bolting. Winter celery requires no hardening. Greenhouse temperatures should be around 65 to 70 degrees F. Greenhouse plants often are given dry or liquid chem- ical or organic fertilizers, but this is not necessary when the right amount of fer- tilizer is included in a light soil-mix. • If late blight appears on plants they should be sprayed with a fungicide such as zineb, maneb, dyrene, bordeaux mix- ture, or fixed copper. Just before trans- planting into the field, appropriate insec- ticides may be added to the copper spray to control aphids or other insects. The number of flats used per acre of [8] field varies from 350 to 400 (most grow- ers use about 375). Field planting can be done directly from flats, or plants can be pulled and taken to the field in crates — which saves hauling of flats and thus lessens time spent repairing them. Growing transplants in outside beds. Celery plants can be grown in open beds in summer and in cloth-covered beds (or cold frames) in winter. Beds should be located near ample water, away from weeds and trash, and on nematode-free soil which does not crust easily; soil should not have been previously planted to celery or related vegetables, such as carrot, parsley, or parsnip, because of danger from disease and insect organ- isms. Beds should be shaped and leveled like those used for field plantings. Three to four ounces of seed will be needed to produce the 35,000 to 44,000 plants re- quired per acre, according to the plant and row spacing used. One acre of seed- bed will produce enough plants for 15 to 20 acres of transplanted celery. After surface of plant beds has been finely pulverized, seeds may be broadcast by hand or seeded in wide bands with small drills. Seed should be covered with not more than % inch of soil. • An irrigation should immediately fol- low seeding, and beds should be kept moist until plants are up — do not allow a crust of soil to form over seeds. Fre- quency of irrigation may be reduced when plants are up, but plants should be kept growing vigorously until shortly be- fore transplanting time. About 2 weeks before transplanting to the field, plants are hardened to withstand the move. Care is required here: overhardening can be harmful, and plants should not be allowed to suffer severely from lack of moisture. Transplanting. Plants are ready to transplant when they are 4 to 6 inches high and about % inch in diameter, but planting dates vary in different districts. In some areas, the dates are restricted by an order adopting California Depart- ment of Agriculture regulations pertain- ing to host-free districts and periods (western celery mosaic) . The counties of Los Angeles, San Luis Obispo, and Mon- terey have the following host-free (celery- free) periods outside of greenhouses: Los Angeles County, July 11 to Septem- ber 30; San Luis Obispo County, January 1 to February 14; Monterey County, Jan- uary 1 to January 31. Growers should check with the Agricultural Commis- sioner to get data on additional regula- tions on districts. Celery transplants are set in the field by machine or by hand. Some growers believe that hand transplanting in the field is faster, but most agree that ma- chine planting has certain advantages: it enables a small crew to plant large acreages more easily and efficiently and it places plants into moist soil at a uni- form depth. Celery may be transplanted on single or double-row beds. On a single-row bed, plants are spaced 5 to 8 inches apart in rows 24 to 40 inches from center to center. On a double-row bed, they are spaced 7 to 10 inches apart ; the beds are 40 inches from center to center and are usually ridged, with the plants set half- way up the sides of the furrow. "Scratch- ing" (a hand-weeding process) and cul- tivating are done later to control weeds and reshape the beds so that rows are on top and not in the furrow. Plants are sometimes set in bottoms of furrows and it is customary (especially during hot weather) to run small streams of water slowly down the furrows as plants are being set. Occasionally, plants are placed on flat top beds as in direct-seeding. If 350 flats, averaging about 100 plants each, are planted per acre, approximately 40 man hours per acre are required to transplant. Direct-seeding. Seed is placed % to % inch deep with a small-seeded vegetable planter, using 1 to 1% pounds of seed per [9] Continued on page 14 ft , ' - 'm&zyKm. CELERY SEEDLINGS in an Oxnard greenhouse. These plants are about ready for transplanting into the field — some will go to the Arroyo Grande area and some farther north to Salinas. The transplant operation IN THIS GREENHOUSE operation, soil from the pile in background is put into flats which are then placed in the sterilizing apparatus. Note how top of sterilizer fits into a slot to seal the chamber. TRANSPLANTING SEEDLINGS into a field near Arroyo Grande (above). These plants were grown in a greenhouse in Oxnard and shipped north the day before transplanting. Transplants may also be set by machine. RIGHT, CLOSE-UP OF TRANSPLANTING operation. Irrigation water is run down furrows as seedlings are transplanted. Workers dip roots into water before placing them into soil along- side the furrow. IRRIGATION AFTER TRANSPLANTING (below right) gives new plants more chance to overcome shock of handling. [ii] 90zmmM DIRECT SEEDING with a regular small vege- table seeder in a single row operation near Arroyo Grande. Direct seeding in the field . . . THINNING WITH HAND HOES. Workers on a planting near Salinas are chopping out unneeded plants, leaving remaining plants at 5 to 10-inch spacings. \?.;V DOUBLE-ROW PLANTINGS are character- istic of the Salinas area. 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