Specialty Crop: Capers
Look for more specialty crop information in the Small Farm Program's Specialty and Minor Crops Handbook - Second Edition
Capers are native to the Mediterranean area and the tropics. The plant, a deciduous dicot, has a very deep root system, grows about two feet tall and has vines 7 to 10 feet long. The flowers are bisexual and have a lifespan of 24 to 36 hours. Each plant produces hundreds of flowers each season. The mature fruit is 2 to 3 inches long and ½ to 3/4 inches in diameter. It starts out green, but turns purple when mature. Each fruit contains 200 to 300 seeds.
Capers are produced in Morocco, Spain and Italy. In Greece, Cyprus, and Turkey, the plant is well adapted but is not cultivated commercially. The United States imports more than $20 million worth of processed capers each year.
Capers are used as a condiment in salads or sauces, or with meat or fish. They also are used in manufacturing cosmetics and medicines. Some Capparis species are poisonous. Depending upon the part of the plant that is used, capers can be considered a vegetable (the edible shoots) or an herb (the processed buds). Because of its attractive flowers and foliage, the caper plant can be used in ornamental plantings. It may also be used to control soil erosion, especially on slopes where irrigation is difficult and soil erosion is more pronounced.
Propagation and Care.
The plant needs little care. It is drought resistant, but requires good drainage. It has few disease or insect problems. Propagation is best accomplished from roots or cuttings because of the variability found in seed propagated plants. Root the cuttings in a greenhouse for at least one year, and then plant in the field on an 8- by 8-foot grid during February or March. In the first two summers, new plants require two to three irrigations. Older plants need less irrigation except in dry years and very hot summers. Spring fertilization is advisable, with irrigation after each application.
Seedlings are very temperamental when transplanted, and some may die. To reduce this loss, transplant with soil attached to the root system, and water immediately after transplanting.
Germination of caper seeds is difficult, but the following methods have resulted in 40 to 75 percent germination. First, heat some water to 110¡F or 115¡F, and put the seeds into the warm water to soak for at least 12 hours, during which time you can allow the water to cool to room temperature. After 12 hours, discard the water, wrap the seeds in a moist towel, place them in a plastic bag, and keep them in the refrigerator for 65 to 70 days. Then take the seeds out of the refrigerator and soak them in warm water (110-115¡F) overnight.
Plant the seed about ¼ to ½ inch deep in a soil mix of 50-25-25 parts of UC soil, perlite and sand, respectively (planting mix can be used instead of UC soil mix). Use 6 inch clay pots or deep flats. Water well and keep in a warm area (70-85¡ F.), in partial to full sun. Do not allow the top of soil to crust over. Keep the soil moist. Germination should start within 3 to 4 weeks and may continue for 2 to 3 months. Not all seeds will germinate at the same time.
Let seedlings grow to 3 to 5 inches tall before transplanting. If seedlings are too crowded in the clay pot or flat, do not pull them - use a scissors and cut off the small, less vigorous, plants, leaving the root systems of the remaining seedlings undisturbed.
Transplant the seedlings to individual 1-gallon containers, using the same planting mix as mentioned before. When transplanting, disturb the root system as little as possible, keeping some original soil around each transplanted seedling. Good soil drainage is essential to prevent root rot. Pack the soil tightly around the transplanted seedling and water immediately. Cover each container with a plastic bag. Keep in a shaded spot in spring or summer, or in a warm area (70-85° F) in winter. Keep the plastic bag in place for one week. At the end of the week, cut off the top of the bag so that the seedling will be exposed gradually to the natural environment. In another 10 days, enlarge the opening in the plastic bag. One week later, remove the plastic bag entirely, keeping the plant in a shaded area. Keep the plants in their 1-gallon containers and then transplant them in early spring after the last frost, when soil is workable.
Plant the capers in elevated rows. The rows should be 8 to 10 feet apart, and the plants in each row should be 8 to 10 feet apart within the row. Water frequently, but make sure that drainage is adequate, and fertilize two to three times during the spring and summer months. Irrigation is essential for the first two years of development. Do not prune the young plant for the first two years. Prune 3-year-old or older plants to the ground (soil surface) during November or December. Cut the canes back, but only 3 or 4 inches from the crown - cutting the canes all the way to the crown may kill young plants.
Harvest and Postharvest
In the spring, pruned plants develop tender new shoots that can be eaten as a vegetable. Pick the buds from mid-May to mid-August. A 2-year-old plant produces a few buds, a 3-year-old plant produces slightly more than 2 pounds in a year, and a plant older than 4 years may produce more than 20 pounds of buds per year. Unopened buds are picked by hand, sorted, and pickled in brine.
Curing and Packing Capers
Sort the harvested caper buds by size: small, medium, or large. Place sorted buds in a strong brine (1 ¼ to 1 ½ pounds of salt per gallon of water - a salt hydrometer or salometer will show 15 to 18 percent or 60 to 72 degrees). Keep the capers in brine for 30 to 45 days. They can stay in the brine up to 12 months without damage, but make sure they remain submerged. When you remove them from the brine, rinse them in running water for several minutes to remove excess salt. Pack capers into small jars, up to the shoulders of the jars. Cover the capers with an acidified solution of 1 gallon of 5 percent vinegar in 2 ½ gallons of water and 1 ½ teaspoons of salt. Leave ¼- to ½-inch headspace between the top of the liquid and the rim of the jar. Adjust the lid and screw it down tight. Do not over-tighten the lid. Jars of capers in acidified brine can be kept in the refrigerator for as long as six months, or they can be pasteurized by submerging them in a hot water bath of 170 to 175¡ F. Once the jars are in the water bath and the water temperature returns to 170¡ F, process the jars for 30 minutes. Remove the jars from the water bath and allow them to air cool. Shelf life of pasteurized capers is about 1 ½ years at room temperature.
Pests and disease
In California, caper plants can be damaged by gray mold fungus, nematodes, and insect pests such as cabbageworm, black vine weevil, and flea beetle. Gophers, snails, and slugs also can cause leaf destruction.
Demetrios G. Kontaxis, Pest Management/ Public Information Program Advisor Contra Costa County, University of California
The caper fruit is 2 to 3 inches long and about ½ inch in diameter (photo by D. Kontaxis).