Introduction to Blueberry Production for Fresh Markets

By Sue Gray, MS, Tulsa County OSU Extension Horticulturist

Sue Gray has worked the past 19 years serving the commercial and home garden sectors of Tulsa County. She has also worked as a technician in fruit, vegetable and pecan research and as a horticulturist for the Maryland Cooperative Extension Service. Sue has a BS in horticulture from OSU and a MS in horticulture from the University of Maryland.

Blueberries are an excellent choice for fresh market fruit production in Northeast Oklahoma and Arkansas. They are in high demand by consumers, are not as perishable as other berries and have few insect or disease problems. They are the only fruit that can be grown organically with a reasonable profit.

Arkansas currently has 450 acres in blueberry production, 80% is sold as fresh market fruit and 85% of the crop is hand harvested. It represents less than 1% of US production. The leading blueberry growing areas are Michigan, New Jersey, North Carolina/Georgia and the Pacific Northwest.

Success in growing blueberries relies on understanding the nature of the plant. It is a member of the Ericaceae or Heath family. Other members of this plant family are azaleas, rhododendrons, and cranberries. These plants all share the following cultural requirements with no room for "bending the rules": They must have an acid soil that is well-drained, but contains high levels of organic matter. They must be heavily mulched to insulate the fine, fibrous roots from temperature fluctuations and to conserve moisture. Drip irrigation is essential.

Southern Highbush Vaccinium corymbosum

There are many species of blueberries in the U.S., as they are native to North America. The three most commonly grown species for this area are: Northern Highbush blueberry (Vaccinium corymbosum), Southern Highbush blueberry (Vaccinium corymbosum x V. spp.) and Rabbiteye blueberry (Vaccinium ashei).

While all three types will grow in both Arkansas and Oklahoma, the Northern Highbush is best adapted north of Interstate 40, the Southern Highbush will grow in all parts of both states and the Rabbiteye will grow best in the southern areas of these states. All three types grow well at the University of Arkansas Fruit Research Station in Clarksville.

Commercial blueberry plantings need not be large. A one acre planting contains up to 1,000 plants and can support hundreds of customers. A five acre planting would be considered very large for fresh market sales. One person, with a bit of help at harvest time, can manage a one acre planting as a part time endeavor. Larger plantings will require more labor, time and the hiring of extra help or family members.

Marketing of fresh blueberries can be done by way of roadside stands, pick-your-own sales or at farmers markets. Expect to begin selling blueberries the third summer after planting.

Yields will be between 400 and 800 pounds per acre the third year, increasing to several thousand pounds per acre as production increases each year.

A site for blueberries should be selected based on soil type and drainage. It should also be in full sun. An ideal soil should be a sandy loam that is well-drained. Heavier soils will require raised beds or rows and the addition of much more organic matter.

Planting blueberries should never be done without careful soil preparation and planning. Good growers know that they must spend a season getting their land ready before planting. This means controlling perennial weeds, such as Bermuda grass, Johnsongrass and other competitors. Soil must be tested and adjusted to a pH of between 4.4 and 5.0. Soil testing will also indicate the needed Nitrogen, Phosphorus and Potassium levels required for blueberries. Organic matter levels must also be high. Blueberries grow best in soils that are a minimum of 3% organic matter. This extra test can be requested from University soil testing laboratories. Many farmers plant green manure crops leading up to planting blueberries to control weeds and add increase soil organic matter levels.

Very finely ground sulfur is used to acidify soil for blueberries. This should be added according to soil test recommendations at least six months before planting. It takes time for the soil matrix to chemically react with the sulfur and effectively change the pH to acid conditions.

Blueberries growing in soils with a less acid pH (above 5.5) will show signs of iron chlorosis..foliage will be yellow with green veins. The iron is chemically bound to soil particles when pH is too high, making it unavailable to the plant.

Blueberries are normally fertilized with ammonium sulfate {(21-0-0) + 18% sulfur}. It is added to soil each growing season in split applications to maintain growth. Organic growers use fish waste, compost and other organic materials to stimulate growth. Foliar sprays of fish emulsion plus liquid seaweed have been effective fertilizers on organic plantings.

Quality irrigation water is essential for blueberries. Have water tested for "irrigation use" by your state university soil and water testing lab. Blueberries are highly sensitive to elevated levels of chlorides, sodium and boron. Well water that contains high levels of any of these elements is not suitable for watering blueberries. Some growers use pond water, but it must have a dual filter system to keep particulate matter out of drip irrigation emitters.

Water pH is also important. Water with a pH above 7.0 may need a small acid injection pump to acidify the water being applied to blueberries.

Planting blueberries can be done in fall or later winter. Most growers order two year old container-grown plants. The advantage is a large root mass that can get better established on new sites. Rooted cuttings, though cheaper, should not be planted directly. They should instead be grown in a small nursery area for a year, then transplanted to the field.

Plant at least two cultivars of each type of blueberry. For example, if growing northern highbush blueberries, select two cultivars, such as `Bluecrop' or `Toro' to insure cross pollination, larger fruit set and a dependable crop. Honeybees, bumblebees and wild pollinators all serve to pollinate blueberry flowers.

Set plants five feet apart in rows that are ten to twelve feet apart. Plant a low- maintenance, non-creeping grass, such a tall fescue, between rows.

Set plants at the same level in which they grew in the nursery, working into the soil one gallon of pre-moistened peat moss per plant. Mulch with at least five to six inches of pine or hardwood mulch. Sawdust may be used, but should be mixed with the chips to prevent crusting. Repeat mulch applications yearly.

Remove blueberry flowers the first two years they are growing. This puts all the plant's energy into getting established in the field. Failure to remove flowers will result in a pre- mature fruit crop, greatly shortening the life of the fruit planting.

In the third year, plants will flower in early spring with a crop following in two to three months. Harvest is generally in early to mid-June in our area. Birds can remove up to one third of a blueberry crop. Growers and researchers have found that one-inch wide holographic bird-scare tape is very effective. Place tape in the planting BEFORE fruit is ripe. It's much harder to eliminate a bird problem once it begins.

Pick berries into one pint containers when they are dark blue with a light grey, waxy bloom on fruit. Get them to a shady place as soon as possible. Blueberries will stay fresh up to two weeks at 34 degrees F. and high humidity. Most small growers either sell their crop in the field to customers or hold a small amount for market sales. They have found that moving the pint containers to an air conditioned area with a fan nearby to move the field heat out of fruit will help keep them fresh for a few days.

County Extension educators can assist growers with any disease insect problems that might arise. Such problems are not common in this area. Weeds are another matter. Make sure weeds are controlled correctly right from the beginning. Both Oklahoma and Arkansas have resource materials available on herbicides labeled for use in blueberries.

For additional information consult these resources:
University of Arkansas Cooperative Extension:
BLUEBERRIES
ATTRA (Appropriate Technology Transfer for Rural America):
ORGANIC BLUEBERRY PRODUCTION
Northwest Berry and Grape Info. Network:
BERRY AND GRAPE INFORMATION NETWORK
North Carolina State University:
NORTH CAROLINA UNIVERSITY, HORTICULTURE