Something about Strawberries
Joan Allen, Assistant Cooperative Extension Educator in Residence
UConn Home & Garden Education Center
Strawberry Facts
Strawberries (Fragaria spp.) are a member of the botanical family Rosaceae, making them relatives of plants like rose, peach, apple, hawthorn, and raspberry. As members of the subfamily Rosoideae, they have aggregate fruits that are made up of small achenes or druplets, and the fleshy part of the fruit is actually the receptacle or stalk of the flower. The latin "fraga" for aroma is the origin of the genus name Fragaria. The common name strawberry may have come from "strew berry" based on the way the berries are strewn out among the leaves.
There are few mentions of strawberry in early historical records because it was not cultivated in the earliest agriculture. The earliest reference to strawberries dates to 234 BC in Italy and another very early written record is by Pliny in the first century AD. The ancient Romans used all parts of the plant for treatment of medical problems such as diarrhea, gout, skin disease and digestive conditions. During the 13th century, it was considered an aphrodisiac. Cultivation began in the 1300s in France and by the 1400s strawberries were being sold by street vendors in London. By the 1500s, mention of strawberries increased in both medical and botanical writings. Strawberries native to eastern North America (Fragaria virginiana) were introduced into Europe in the 1600s and crosses of this species with European plants were the beginnings of the big- fruited plants cultivated today. Native Americans began cultivating the strawberry in the 1640s and the early European settlers of Massachusetts loved them. It took a while for cultivated strawberries to become popular and finally between the late 1700s and 1820, the number of varieties introduced went from 3 to 30. Cultivation of strawberries began in California around 1900 and that state now supplies almost 80% of the nation's crop.
Where to Grow Strawberries
The best site for strawberries has full sun and is free of low spots that may allow for frost pockets or poor drainage. They can do well on many soil types. A good supply of organic matter and well drained soils are desirable. Sandy soils will require irrigation. If the site is poorly drained, strawberries can be grown in raised beds. The preferred pH is 5.5 to 6.5. A soil test will determine if lime should be added to increase the pH prior to planting. Fertilization before planting should also be done based on the results of a soil test. An additional application can be made in mid to late August of the first year at a rate of one pound of 10-10-10 or similar fertilizer per 100 ft2. Organic materials such as compost can be substituted. It is important to eliminate weeds, especially grasses and other perennials, prior to planting.
The Strawberry Plant
Strawberries have a unique root system. The fibrous roots live for only one year and new roots are grown each July above the old roots. Most types of strawberry reproduce by runners. The production of runners is day length dependent and decreases as the days shorten. Daughter plants form on the runners and will form roots if in contact with the soil. New crowns are formed from buds in the leaf axils. Flower buds for the next spring are formed at the tips of the crowns from September through November.
There are three types of strawberries commonly grown in cultivation: June bearing, day neutral and everbearing. June bearing varieties produce one major harvest that lasts two to three weeks. There are early, mid and late season June bearers and planting varieties from each group can extend the harvest season. The day neutral varieties produce flowers and fruit without regard to day length. These will produce berries all season long. They produce fewer runners which can be an asset in a small garden. Everbearing strawberries have a misleading name. They produce two harvests, one in spring like the June bearers and another smaller late summer crop. They tend to have a smaller berry size and are fading in popularity since the introduction of the day neutrals.
Select varieties that are resistant to the diseases red stele and Vertillium wilt. Other diseases affecting strawberry include black root rot, gray mold and leaf spots. Insect pests include the strawberry clipper, tarnished plant bug, thrips, aphids, white grubs and others. Slugs can also be a problem.
First Season Planting and Care
As few as two dozen plants can supply enough berries for a family of four. Plant strawberries in early spring as soon as the soil can be worked. Keep plants in storage as close to 32° as possible until ready to plant because strawberries will begin to grow as soon as the temperature is above freezing. Place plants in holes large enough so the roots can be spread and deep enough so the soil is halfway up the crown. Water immediately after planting. The best planting system for most gardens is the matted row. Space plants 18" apart within rows 48 to 52" apart. This allows room for runner growth and daughter plant development. During the first season, remove all flower buds on June bearers to increase runner development and plant vigor. Flowers forming on day neutral and everbearing varieties may be left on beginning in July. Maintain row width at 24" by placing runners within this space before they root or by removing some of them. Plants should receive 1-2" of water per week from rain and supplemental irrigation as needed.
Weed control is important in strawberry beds. Frequent cultivation by hoeing or hand pulling will increase yield and extend the life of a strawberry planting.
Strawberry plantings will be productive for two to five years if plants are kept healthy and vigorous. After harvest is complete, the bed should be renovated. First, mow all the leaves off the plants if they are June bearers. Skip this step for day neutrals and everbearers. Use a mower at its highest setting. Fertilize at the rate described above. A couple of weeks after mowing, narrow the rows to 10-12". Between Thanksgiving and Christmas apply a winter mulch of straw, pine needles, or a similar material. The mulch layer should be 3-6" thick. In early spring pull the mulch back and leave it between the rows as soon as growth begins. This will help keep the berries clean, control weeds, retain moisture and create a clean walkway. If frost is expected, mulch can be raked back over plants for protection overnight.
Harvest
The best time to pick strawberries is determined by color and the firmness of the variety. Varieties with a firmer berry may be picked when fully red. Softer varieties should be picked when the fruit still shows a little pink or green. Pick berries by the stem so the calyx "cap" is left on. This improves storage life. Avoid bruising the fruit. Picking every other day is usually adequate but in hot weather, which hastens ripening, you may need to harvest every day. Enjoy your berries! For more information on growing strawberries or other plants, contact the UConn Home & Garden Education Center toll free at (877)486-6271 or by email at ladybug@uconn.edu.
References
Darrow, G. M. The early history of the strawberry. http://www.nal.usda.gov/pgdic/Strawberry/book/bokthree.htm Accessed on January 20, 2010.
Gauthier, N. L. and E. L. Marotte. 1990. Strawberries. Connecticut Cooperative Extension System, University of Connecticut, Storrs, CT.
Handley, D. T. 2003. Growing strawberries. University of Maine Cooperative Extension Bulletin #2067.
Otto, S. 1995. The Backyard Berry Book. 284 pp. OttoGraphics, Maple City, MI.
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