Celery and closely related Celeriac both belong to the genus Apium of the Carrot or Umbelliferae Family which includes some 20 species of herbs that are best adapted to the northern temperate zone.
Celery is one of the more difficult crops to grow in the home garden because it requires more detailed care than most other crops. It is a cool weather plant and, therefore, in the south it is grown as a winter and spring crop and farther north as a summer and fall crop.
The more important commercial production areas are located in Calif., Fla., and Ariz. in the south and N.Y., N.J., Mich., Ohio, Pa., and Wash. in the north.
Green varieties have increased in importance and the so-called yellow or self-blanching types have decreased in use during the past 20 years. The most important green varieties are ‘Utah’, of which there are number of strains, ‘Giant Pascal’, ‘Summer Pascal’ and ‘Fordhook’. Varieties in the self-blanching category are ‘Golden Self Blanching’, ‘Wonderful’ or ‘Golden Plume’, ‘Michigan’ and ‘Detroit Golden’.
Celery Soils and Fertilizers
No garden crop grown is such a rich feeder as Celery. The soil must have depth, mellowness, and an abundant supply of moisture. A well-drained muck or peat soil is ideal but most home gardeners will find a sandy loam soil that is well supplied with organic matter to be very satisfactory. A heavy clay soil should be avoided. The soil pH should range between 5.8 and 6.7.
For sandy loam soils, bushels of animal manure or well-decomposed compost should be thoroughly plowed or spaded into the soil to a depth of 7-8 in. Celery is a heavy feeder and a poor forager and, therefore, in addition to the manure or compost it is advisable to broadcast, at the time of plowing or spading.
Raising Celery Plants from Seed
Most home gardeners will find it more desirable to buy plants from a dealer or commercial grower. Celery seed is small, germinates slowly and must have careful attention as to temperature and soil moisture during the germination period.
The seed should be planted in a very light sandy soil, preferably in drills 11-12 in. apart. After the seed is covered a piece of burlap or even a newspaper is placed over the flat or container to help maintain uniform moisture of the soil during the germination period. Temperatures of 70-75°F. are optimum.
The young seedlings are very delicate and spindly until they reach a height of I-1-2 in. When the second true leaves appear the plants should be transplanted into a good potting soil 11-12 in. apart. Maintaining a uniform moisture and temperature is very important introducing a good stocky plant. Temperature exposure of 50° F. or below, for 7 days or more, will result in premature seed-stalk development. Some 8-9 weeks are necessary before plants are ready for out-of-door planting.
Celery Planting and Care
The garden soil should be fine, smooth, moist and fairly firm and the plants stocky, 4-5in. tall with plenty of roots. Out-of-door planting should be delayed until danger of frost is past. Planting distance, 5-6 in. in the row and 24-30 in. between rows. In planting set the plants level with the crown of the plant or not deeper than they were in the flat or seedbed. The young plants should be watered daily until they are well established.
Shallow cultivation should start as soon as possible after planting in order to control weeds and to maintain a thin, loose surface of the soil.
Celery will respond to several applications of nitrate of soda during the growing season. Each application of 3-4 lbs. per too ft. of row should be placed several inches from the plants on both sides and then lightly worked into the top surface of the soil. Watering will help to make the fertilizer available to the plants.
Celery Blanching and Harvesting
Blanching means the loss of green color and since it is known that the green color of plants contains higher vitamin A content than non-white parts the demands for blanched celery has materially decreased.
Blanching of the self-blanching or early types is usually done by the use of wide rolls of heavy building paper boards which are placed on either side of the row of Celery and then held together by wire hooks.
For the late varieties the most satisfactory method of blanching is to gradually pull soil around the plant until only the top of the leaves show above the mound. No soil must be allowed to fall into the heart of the plant. This type of blanching should not be done until late in the fall or when the plants are fully grown. Placing hay or straw over the hilled row will mean that the plants can be kept until early winter.
There is no definite stage of maturity at which Celery must be harvested. Its best quality is attained when the plants have reached full size. In harvesting the plants are cut off below the surface of the soil with a large knife. Pull off the outside stalks and use them for celery soup or flavoring.
The fall crop of Celery may be stored for periods of 4-8 weeks. Perhaps the most practical method for the home gardener is in using a trench in the garden area. Three to 4 rows of Celery are packed tight and upright in the trench. Boards are set against the side and over the top of the trench. Hay or straw is then placed over the boards and as colder weather sets in a layer of soil is placed over the hay. Cold frames may also be used to store Celery for short periods.
Celery Diseases and Insects
Celery is subject to a number of diseases and insects, but only a few are generally of importance. Early and late blight are carried over from year to year in the seed and on old Celery plant refuse. In the home garden the most satisfactory control is the use of a copper-lime dust or Bordeaux mixture (4 oz. copper sulphate, 4 oz. hydrated lime to 3 gals. of water) as a spray applied at weekly intervals.
Bacterial leaf spot, root rot and yellows are other diseases which may be important. Insects that may be important are the carrot rust fly and the tarnished plant bug. The latter insect may be controlled with dimethoate. Be sure to read the label.
Two physiological disorders are frequently important, namely, black heart and cracked stem. Black heart first shows as a tip burn on young leaves and then spreads to the heart tissue of the plant which in severe cases is killed and turns black. This condition probably is due to deficiency of calcium and an imbalance of other nutrient elements in the soil. Cracked stem results in brownish cracks and lesions on the inner and outer surface of the leaf petiole. This condition can be controlled by adding small amounts of borax, to the fertilizer used prior to planting or in applying borax as a solution near the base of the plant.