Growing Blueberries in the Home Garden

Blueberries are an immensely popular fruit in the United States because of their unique flavor, small, soft, and edible seeds, and their easy use in preparation (Figure 1). Blueberries can be eaten fresh or used to make jelly, jam, pies, pastries, or juice. Blueberry fruit is also low in calories and sodium, contains no cholesterol, and is a source of fiber. A major constituent of the fiber is pectin, renowned for its ability to lower blood cholesterol. Blueberries, like blackberries and strawberries, contain measurable quantities of ellagic acid, which has inhibiting effects on chemically-induced cancer in laboratory studies. Blueberry juice also contains a compound that prevents bacteria from anchoring to the bladder, thereby helping to prevent urinary tract infections.

Should I Grow Blueberries at Home?

Blueberries can make a good fruit crop for home gardens since they require little space and have minimal spray requirements. At present, blueberry plants are not common in home fruit plantings because the plants require very acidic soil conditions in order to grow and thrive. Few backyard soils in Ohio are naturally acidic enough to grow quality blueberries. Therefore, any successful grower of blueberries must take precautions to check and correct soil acidity before planting. Blueberries grow best in moist, well-drained soils with a soil pH between 4.0–5.2 and high organic content (Gao et. al., 2019). Once the plants are established, the acidity level must be monitored and maintained over the life of the planting. Due to the highly specialized and specific growing conditions, the soil must be amended with organic matter, and the pH must be corrected before proceeding to establish the planting. Refer to the sections on soil preparation and suggestions for soil acidification for more information.

Bare-rooted blueberry plants begin to produce fruit in the second or third season; however, they do not become fully productive for about six to eight years (Figure 2). Container-grown blueberry plants may be 2–3 years old and may produce berries during the year of planting. Blueberry plants should not be allowed to bear fruit during the first two years after planting or until the plants reach a height of 2.5 feet. Any blooms that form should be removed. Allowing the plant to fruit will reduce growth and result in a small plant. Removal of flowers will allow more shoot growth and increase yields in future years. Once in production, it will be necessary to protect the fruit from hungry birds before the fruit begins to color.

Blueberry Types and Cultivars

Five types of cultivated blueberries are grown:

• Northern highbush
• Southern highbush
• rabbiteye
• lowbush
• half-high

(Finn et al., 2024).

Only northern highbush and selected cold hardy hybrids of northern and southern highbush blueberry are recommended for Ohio. Rabbiteye and southern highbush blueberries are recommended for the southern United States. Lowbush blueberries are commonly grown in the wild, and, in Maine, they are harvested as a commercial fruit crop. Half-high blueberries are better suited for extremely cold winter conditions as in Minnesota and Wisconsin and may not be as productive as highbush blueberries.

Many good blueberry cultivars are available. Refer to Table 1 for blueberry cultivars suggested for Ohio. Highbush blueberries differ in their self-fruitfulness. Most of them do not require two different cultivars for cross-pollination. However, higher yields will result from cross pollination of two different cultivars, thus it is desirable to plant at least two different cultivars. Using multiple cultivars also allows growers to lengthen the harvest season and assure good crops if one cultivar has an “off” year, meaning a year with low yields.

Climatic Requirements

In general, Ohio’s climate is well suited to the production of blueberries. Northern highbush plants can suffer winter injury to flower buds when temperatures drop below  -20 degrees Fahrenheit. However, the lowbush blueberries will tolerate -35 F to -45 F. Note that lowbush blueberries grow from 3 to 4 feet tall so most of the fruiting area is protected below the snow line.

Site and Soil Requirements for Blueberry Production

Blueberries require full sun (6–8 hours of sunlight per day) for optimum yield and quality, and grow best where the soil is very acidic and moist (Gauthier et al., 2013). The soil pH should be in the range of 4.5–5.5, with an ideal pH of 4.5 and 4%–7% organic matter or more. For soils with high loam, clay loam, or clay content, it is strongly suggested that plants be grown in raised beds 4 feet wide and 9 inches high for better water drainage. Such beds are not needed on sandy soils.

Soil Preparation

It is particularly important to test soil for pH, lime index (buffer pH), nutrient status, and organic matter content before conducting soil preparation. Refer to Ohio State University Extension fact sheets, HYG-1132, “Soil Testing for Horticultural Needs,” (cfaes.osu.edu/fact-sheet/soil-testing-horticultural-needs) and HYG-1133, “Guidelines for Choosing a Soil Analytical Laboratory,” (ohioline.osu.edu/factsheet/HYG-1133) for more information on soil testing lab selection and soil testing procedures. Your soil should be tested twice: once before soil preparation and acidification and once after the addition of sulfur and fertilizer. Further adjustments may then be necessary. Please contact your local Extension office for information on soil testing. Increase soil organic matter by adding organic materials, such as peat moss, aged wood chips, or leaf mold or humus. Incorporate the materials into the top 4–6 inches of the soil at least one year before planting.

Suggestions for Soil Acidification

If soil pH is above 5, apply granular sulfur to lower soil pH. Refer to Table 2 for general guidelines on the amount of elemental sulfur needed to be applied to acidify 100 square feet of soil. Elemental sulfur, also known as soil sulfur, comes in the form of pellets, granules, or powder (Figure 3). The material should be well-mixed throughout the top 4 inches of soil, three months before planting. Longer periods of time may be necessary if the soil pH is above 6 and contains high levels of calcium. In these cases, sulfur should be applied the year before planting and the soil should be kept moist but not wet. Soil bacteria convert sulfur to sulfuric acid in warm moist conditions during the growing season. This process does not occur during the winter. Wear gloves when handling any form of elemental sulfur.

Planting Techniques

Spring is the best time to plant blueberries. Soak the roots of bare-rooted plants in water for an hour before planting. It is also recommended to prune back the plant by half. This can be accomplished by pruning off smaller shoots and by heading back the main branches. More and more garden centers carry container-grown blueberry plants. These plants have a much bigger root mass, thus have a much better chance of survival and getting established. Be sure to break up the root ball when planting container-grown plants to assure that the plant roots will grow out of the peat medium in the pot and into the soil.

Dormant blueberries can be planted in the spring. Plants that have broken dormancy and are actively growing (green buds or shoots) should be held in a greenhouse, a garage, or a back porch until after the last average frost date in your area. Remove each blueberry plant from its shipping container and place it in a bucket of water to soak for about one hour before planting.

Mark the exact location where you will be planting each blueberry bush. Highbush blueberries are commonly spaced 3–4 feet apart in rows 10 feet apart. Earlier-season cultivars can be planted closer while later-season cultivars should be planted further apart. Use a shovel or spade to dig a hold two to three times the size of the root system. This will ensure adequate space for the root system to fit in the hole and will also allow peat moss and compost to be added as needed.

Once a hole is dug, add approximately one gallon of peat or sphagnum moss to the planting hole. This medium should be thoroughly mixed with the natural garden soil during the planting process. The root system should be spread out to fill the hole evenly. Position the root crown level with or slightly below the soil surface and backfill with the soil/peat moss mixture. Be careful not to place plants too deep or too shallow. Once planting is complete, water each bush to promote good root-soil contact that will help keep the root system from drying out.

When planting container-grown blueberry bushes, gently remove the plant from the pot and lightly roughen up the outside surface of the root ball with a hand pruner. Set the top of the root ball about 1–2 inches lower than the existing ground and backfill around the root ball. Cover the exposed roots on top of the root ball with peat-soil mix. Water the plant thoroughly.

Apply 4 inches of sawdust or wood-chip mulch in a 2-foot-wide band after planting and maintain a 4-inch depth and 4-foot-wide band throughout the life of the planting.

Fertilizers

Fertilizers for blueberry production are best applied using soil-test results as a guide. During the year of planting, apply ¹/₂ to ²/₃ pound of ammonium sulfate (or 10 ounces to one pound of 10-10-10) per 100 feet of row about four weeks after planting. Another option is to apply a fertilizer designed for acid-loving plants, such as rhododendron food. Keep fertilizer at least 6 inches away from the stems of the plant.

In the second year and succeeding years, apply 1 to 1 ¹/₂ pounds of ammonium sulfate (or 2–3 pounds of 10-10-10) per 100 feet of row each year for fertility and acidity maintenance. Apply ¹/₂ pound of the ammonium sulfate at bloom and apply the remaining ¹/₂ pound 4–6 weeks later. If plant leaves become chlorotic, apply 2–3 ounces of ferrous sulfate or iron chelate around the base of the plants each year. Fertilizers, such as rhododendron food, can also be applied during the second and succeeding years if ammonium sulfate is not available.

Watering

Blueberry bushes have very shallow root systems and are extremely sensitive to water fluctuations. Limited water during the fruit-forming period will adversly affect berry size and total yield. When dry, blueberry leaves are leathery and plants do not wilt but stems and leaves begin turning brown and start dying when under drought stress. Blueberry plants require at least 1–2 inches of water per week. Using a soaker hose is an excellent way to deliver water to blueberry plants. During the growing season, supplemental watering is essential to obtain good yields of high-quality fruit. It is important to maintain moist soil all the way into late summer after harvest. Flower buds for the next year form in late August and September so drought stress at this time will reduce yields the following year. Much less water is needed in the fall. Make sure soil is moist but not soaking wet. Watering the plants is not necessary once the leaves drop in late fall.

Pruning

Blueberry plants do not need much pruning for the first three years. Remove small and spindly shoots at planting. Remove blossoms that appear in the year of planting and second year after planting to stimulate vigorous growth.

It is important to know the anatomy of a blueberry bush before attempting to prune blueberries (Figure 4). During the fourth year, the dormant plants should be pruned in mid-March. At this time, remove dead and weak branches, and thin, terminal wood with small buds. Prune interior crossing branches to admit light to the center of the plant. Blueberries are typically pruned to maintain a narrow base and to encourage flowering and fruiting in the upper canopy. Low-growing canes with a more horizontal habit should be pruned from the plant. Consider pruning most horizontal branches growing below knee-height and any branches that could be damaged by equipment such as lawn mowers.

In the subsequent years, remove a few older branches to force new shoot growth from the crown. Head back tall-growing branches and remove thin branches. Blueberry flower buds are produced at the shoot tips and downwards on last year’s shoots. (Figures 5 and 6). Blueberry bushes tend to produce smaller berries when they are overloaded with fruits. Hence, it is important to limit the number of flower buds.

Mulching

Generous use of mulches like sawdust, wood chips, or peat moss will help control weeds, conserve moisture, and keep roots cool. Increased organic matter from decomposing mulch will help improve the soil structure and nutrient uptake of the blueberry bush. Replenish mulch as needed to keep the mulch depth at 2–4 inches. When wood chips or sawdust are used as a mulch, add nitrogen at the rate of one pound of actual nitrogen per 1,000 square feet of mulched area.

Harvesting and Storage

Blueberries do not ripen evenly throughout the cluster and should be picked at least once a week. Only fully mature fruits should be harvested because immature fruit are quite acidic and of inferior quality (Figure 7). Immature fruits have a reddish tinge, while ripe fruit are a uniform blue. Fruits do not develop their full flavor when they first become blue but require one to two days to develop full flavor. Fruit size will continue to increase up to 35% after berries turn blue as water moves into the fruit. Blueberries, unlike some other small fruits, can remain on the plant for up to 10 days after ripening without a loss in size. Fruit sugar content can be as high as 15% when fully ripe. Fruit flavor and sugar content will not improve after harvest. Thus, the best-tasting fruits are obtained if the berries are allowed to ripen fully on the plant; however, the storage life is shorter when berries are fully ripe.

Harvest only when berries are dry. Hands should be placed beneath the clusters to ensure that berries are not dropped. With the thumb, roll blueberries from the cluster into the palm of the hand. The fruit should be handled carefully and as little as possible to avoid rubbing off the bloom (the light waxy finish on the skin) and reduce bruising that leads to decay.

Following harvest, blueberries should not be allowed to remain in the sun. The dark fruit heat up rapidly. At this point, decay is the primary source of berry loss. Anthracnose, gray mold, and Alternaria diseases are the three most common fruit-decay organisms. Decay is more of a problem with fruit harvested late in the season when a significant percentage of fruits are overripe.

The easiest and most effective means of retaining blueberry quality following harvest is to use refrigeration. Low temperatures slow down ripening and reduce decay. Blueberries keep best at 32 F and 85% relative humidity. Freshly harvested blueberries will keep for two weeks at 32 F but only two days at 70 F.

Insects and Diseases

Some potential insect problems in blueberries include blueberry tip borer, plum curculio, blueberry maggot fly, Japanese beetle, cranberry fruit worm, spotted wing drosophila, and cherry fruitworm. Disease problems include mummy berry, powdery mildew, twig blights, botrytis blossom blight, leaf spots, phytophthora root rot, and crown gall (Welty & Ellis, 2010). For more information about growing blueberries, growers should purchase a copy of the OSU Extension Bulletin #940, "Midwest Home Fruit Production Guide” (extensionpubs.osu.edu/midwest-home-fruit-production-guide), and Bulletin #780, "Controlling Disease and Insects in Home Fruit Planting" (extensionpubs.osu.edu/controlling-diseases-and-insects-in-home-fruit-plantings) from OSU Extension offices across Ohio (extension.osu.edu/lao). OSU Extension bulletins can also be purchased from OSU Extension Publishing (extensionpubs.osu.edu).

Acknowledgments

The authors would like to thank Dr. John Strang, former Professor and Extension Fruit and Vegetable Specialist, University of Kentucky, for the use of blueberry harvest and storage information. Our appreciation also goes to Mark Longstroth, former Area Extension Educator, Michigan State University, for the use of a photo.

References

Finn, C., Strik, B., & Moore, P. (2024). Blueberry cultivars for the Pacific Northwest. A PNW Extension publication, PNW656.extension.
oregonstate.edu/catalog/pnw-656-blueberry-cultivars-pacific-northwest

Gao, G., Becker, R., Brown, M., Ellis, M., Prochaska, S., Welty, C., & Williams, R. (2019). OSU Extension Bulletin 940, Midwest home fruit production guide. Ohio State University Extension.
extensionpubs.osu.edu/midwest-home-fruit-production-guide

Gauthier, N., Kaiser, C., Barnes, T., Smigell, C., Strang, J., Wolfe, D., Wright, S., Byers, P., Demchak, K., Ellis, M., Gao, G., Hanson, E., Isaacs, R., Johnson, D., & Stafne, E. (2013). University of Kentucky Extension Bulletin, ID-210, Midwest blueberry production guide. University of Kentucky Extension.
publications.mgcafe.uky.edu/id-210

Welty, C., & M. Ellis. (2010). OSU Extension Bulletin #780, Controlling disease and insects in home fruit plantings. Ohio State University Extension.
extensionpubs.osu.edu/controlling-diseases-and-insects-in-home-fruit-plantings

Originally written in 2017 by Gary Y. Gao, Associate Professor and Extension Specialist, OSU South Centers, The Ohio State University; and Erik Draper, Assistant Professor and Extension Educator, Commercial Horticulture, Ohio State University Extension, Geauga County.