320 Handbook of herbs and spices
phosphorus and potassium are applied at the time of planting and the remainder used
as side dressing (Kadam and Salunkhe, 2001). Areas with minor nutrient deficiencies
require the application of boron, calcium and magnesium for controlling deficiency,
otherwise physiological disorders such as cracked stem, black heart and leaf chlorosis
may occur (Rubatzky and Yamaguchi, 1997). The application of phosphorus induced
a non-significant increase in seed yield but maximum returns were obtained with the
application of 200 kg N and 33 kg P 2 O 5 ha–1 in Punjab, India (Bains et al., 1977).
Seed germination and the emergence of celery plants are slow even when conditions
are favourable. The celery seeds are reported to possess thermo dormancy resulting
in no or slow germination at temperatures greater than 25^ ∞C. A seed soaking treatment
at 10 ∞C using growth regulators GA 4/7 or ethephon at 1000 ppm can overcome this
dormancy (Thomas, 1990). Far red light or sunlight exposure also improves germination
percentages when the seeds are very dormant. Therefore it is advisable to sow seeds
shallow to enhance light exposure. The thermo dormancy and photo dormancy existing
in celery have been reviewed in detail by Desai et al., (1997).
Celery crop may be raised from transplants or by direct seeding in the field. The
time of sowing is determined on the basis of crop to be raised for fresh herb or seeds.
In California, seed beds are sown in July or sometimes December–January. The 8–
12-weeks-old seedlings are transplanted in a well-prepared field. In other parts of the
USA with more severe winters, crops are started in the early spring by sowing in a
greenhouse or hot beds and seedlings are dug in the autumn, rouged for off type and
cold stored until planting time in spring. The tops are stored at 0^ ∞C and 90–95% RH,
maintaining moisture and good ventilation around the roots. The roots are placed in
moist soil. The withered and decayed leaves should be removed when plants are
transplanted at distance of about 90 cm between rows. The closer spacing results in
higher seed yields. In some coastal areas of California, celery is seeded directly in the
production beds. In India the celery is grown as seed spice covering a large area in
the Punjab which is situated in the northern plains. It is grown during September–
October and transplanted from mid-December to the first week of January (Randhawa
and Kaur, 1995). The row spacing of 40 cm gave maximum seed yield. Celery crops
yield about 60–70 t/ha as the fresh herb whereas seed yield of 2–4 q/ha can be
obtained from crops grown exclusively for the purpose, respectively. The seed crop
requires fertilizer dose of 90 kg N, 40 kg P 2 O 5 and 20 kg K 2 O ha–1 for annual
cultivars under semi-arid agro-climatic conditions in India (Malhotra, 2005).
The celery crop is affected by several diseases and insect pests. But insects pose
comparatively less of a problem than do diseases. The main insect pests causing
occasional damage are leaf minor (Liriomyza trifolii) and celery fly (Euleia brercolai)
but carrot rust fly (Psila rosae) may cause occasional damage. The important diseases
of celery include early blight (Cercospora apii), late blight (Septoria apii), Fusarium
yellows (Fusarium apii and F. apii f.sp. pallidum), stem rot (Rhizoctonia solani),
bacterial blight (Bacterium apii), aster yellows (virus) and celery mosaic (virus). The
diseases and insect pests of celery crops have been reviewed in the texts of Thakur
(2000) and Malhotra (2006a,b). Successful chemical control measures for various
diseases and insects pests are available.
The fresh herb crop of celery is harvested when plants are fully grown. The plants
are either pulled off or cut below the soil surface along with petioles attached to the
base. Normally, the salad crop is cut, trimmed and packed in the field. Mechanical
harvesters are also used for harvesting of celery petioles (Swaider et al., 1992). It is
usually ready for harvest 90–120 days after transplanting, whereas direct seeded crop