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1.This document is Fact Sheet RF-AC007, one of a series of the Extension Administration Office, Florida Cooperative Extension Service, Institute of Food and A g ricultural Sciences, Universit y of Florida. First Published: June 1987. Reprinted: Januar y 1997. Revised: Januar y 1997. Please visit the FAIRS Web site at http://hammock.ifas.ufl.edu .The Institute of Food and A g ricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information and other services only to individuals and institutions that function without re g ard to race, color, sex, a g e, handicap, or national ori g in. For information on obtainin g other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative Extension Service / Institute of Food and A g ricultural Sciences / University of Florida / Christine Taylor Waddill, Dean2.Timoth y E. Crocker, professor; Wa y ne B. Sherman, professor, Horticultural Sciences Department; Kathleen C. Ruppert, assistant professor, Florida Ener g y Extension Service, Cooperative Extension Service, Institute of Food and A g ricultural Sciences, Universit y of Florida, Gainesville, FL 32611.Fact Sheet RF-AC007Alternative Opportunities for Small Farms: Blackberr y Production Review1 T. E. Crocker, W. B. Sherman and Kathleen C. Ruppert2Blackberries are one of the easiest to grow and mostYield data approximately 20 years ago, with the best widely adapted fruits. Native species and commercialFlorida varieties at the time, yielded 2 to 3 tons per acre plantings extend from Florida to the Pacific Northwest. whereas 4 to 8 tons per acre in the Pacific Northwest was However, cultivars differ as to winter cold requirementsthe average. There are no proven yield studies on any of and susceptibility to diseases. Therefore, proper cultivarthe newer varieties at this time, although a few selection is important for successful production.demonstration plots are in existence in North Florida and Blackberry production in Florida is currently limited to home gardens and small u-pick plantings. This, in part,In addition, a physiological change from black to red is a result of the high perishability of the fruit and theof some drupelets occurs when blackberries are exposed to thorny inherent nature of the plants themselves. Theonly two hours of heat immediately after picking. varieties that are currently being grown and which areTherefore, they have to be chilled immediately and even adapted to Florida produce large, attractive fruit that arewith chilling, the average shelf life is only two to three used locally. In North Florida there may be somedays. thornless varieties that do well. association in the Marion county area but, due to the highMarketin g SituationCommercial acreage of blackberries in Florida is currently small (less than 5 acres). Commercial processing of Florida grown blackberries is unlikely in the near future as those grown in the Pacific Northwest are under long days during ripening in which they accumulate approximately 12% soluble solids (sugars), whereas those grown in Florida accumulate approximately 9 to 9%Blackberries are currently hand harvested although soluble solids (sugars). Therefore, on a tonnage sugarthere is research on-going in Arkansas with regard to a basis, Florida cannot compete.mechanical harvester. Harvest extends from mid-March to some yield data should be available next season. Approximately 20 years ago there was a blackberry perishability of the crop and several late spring frosts, the association no longer exists. Currently, those people interested in blackberry production will probably have to develop their own local market to have success.Labor and Capitalmid-June, depending on the cultivar and the year. Blackberries are dark when ripe (although some may
Alternative Opportunities for Small Farms: Blackberry Production Review Pa g e 2June 1998revert to red after harvest--see "Marketing Situation") andbloom, and picking of Oklawaha and Flordagrand may red ones are to be left for later picking unless they are tobe in progress before peak bloom occurs on Brazos. The be used for jelly, in which case a portion of slightlylater bloom of Brazos enables this variety to escape frost immature fruit is desirable.damage most years. Both trailing and semi-erect types require the removalAlthough work is on-going with regard to suitable of old canes following harvest. In addition, trailing-typethornless varieties, with demonstration plots being blackberries are trained on a wire trellis. Due to Florida'sevaluated, the thornless variety will be for North Florida, long growing season you can prune both the old and newonly. growth back to ground level immediately after harvest. Plants of trailing varieties may be spaced 5 to 10 feet apartSuitabilit y Blackberries are adapted to a wide range of well-drained soils. A pH of 5.5 to 6.5 should provide optimum growing conditions on mineral soils. A site with good air drainage and frost protection is especially important for the early blooming, trailing types. Mature blackberry plants are seldom damaged by cold; however, damage to flowers and young fruit is frequently a problem in early spring due to late frost. Because of variations in frequency and amount of rainfall, irrigation appears necessary for successful blackberry production in Florida. In general, 1 inch of water per application is sufficient. Irrigation is needed at about weekly intervals during the dry periods of late spring and early summer. The rate of water use increases as daily mean temperature and day length increase. Several kinds of insects including thrips, spider mites,Plantin g SituationThere are several species of Rubus called blackberries. Some are upright and require no support but others are trailing and require a trellis. The trailing types are called dew-berries. Recommended varieties for Florida are (1) Oklawaha and Flordagrand, early fruiting trailing types, released by the Florida Agriculture Experiment Station and (2) Brazos later fruiting, semi-erect type, introduced from Texas. Brazos does not require cross-pollination; however, the varieties Oklawaha and Flordagrand do not set fruit with their own pollen but produce well-formed berries when cross-pollinated. Oklawaha and Flordagrand bloom much earlier than Brazos. The earlier bloom results in an earlier crop, which is an advantage for the fresh-fruit market. On the same site, the trailing and upright types seldom overlap in The cool months are best for setting blackberry plants. in the row between posts that are 20 to 40 feet apart. The spacing between rows is of 10 to 12 feet, but optimum spacing depends largely on the cultivation equipment to be used. Set plants of the semi-erect `Brazos' 4 to 6 feet apart in the rows. For easier picking, tillage, and cleaner fruit, the canes must be supported off the ground. When vigorously grown and properly pruned, the Brazos requires no trellis; however, Oklawaha and Flordagrand require a trellis. There are a number of trellising methods. A common one consists of three evenly spaced horizontal strands of wire with the top one 5 feet high. The wire is supported by well-anchored end posts with smaller sturdy posts within the row.Cultural Pro g ramcaterpillars, stink bugs and beetles may attack blackberries. Control measures for insects have not been needed in some areas, while in other areas a regular spray program appears to be desirable. Fungus diseases appear commonly in blackberry plants grown in Florida. These include leaf spot, anthracnose, rosette or double blossom among others. Generally good cultural care, including cutting back both old and new canes to ground level after harvest (burning all pruned-off parts), tends to offset many disease problems. When chemical control is necessary you should contact your local county extension agent for the most up-to-date recommendations. If the plantings were made during the late fail or winter, no additional fertilizer need be applied until late February or early March when 1/5 lb of mixed fertilizer (i.e. 8-8-8) should be applied per plant. Repeat at 8 to 10 week intervals until early September. During all succeeding years, make 3 applications of lb mixed
Alternative Opportunities for Small Farms: Blackberry Production Review Pa g e 3June 1998fertilizer per application. Make applications in February, June and late August. Weed control is important in establishing and maintaining a vigorous and highly productive blackberry planting. Hoeing, shallow disking and herbicides are recommended. Since blackberries produce shallow fleshy root systems, deep cultivation must be avoided.