- Written by Robbi Hoy
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I don't think I know anyone who doesn't like the taste of fresh blueberries and it seems that for some reason, this year, it has been the plant most often asked about. Although blueberries have specific growing requirements, having them in the garden can be a wonderful treat because nothing beats the taste of blueberries picked fresh from the bush. Blueberries and their relative, cranberries, are the only commercially produced fruit crops that are native to North America.
Blueberries need specific soil and site for best growth and production. They MUST have acidic soil, the preferred range is between pH 4.5 and pH 5.0. They all grow best in a sunny location, but can survive in some shade. As shade increases, flower and fruit production decreases. Well drained soil with plenty of organic matter is best for healthy blueberry plants. Avoid planting in areas with little air movement which has the potential to increase risk of frost damage and death in winter.
Soil Acidity: Test the soil and start reducing the pH at least a year before you will plant. Sometimes the change in pH is easiest to achieve in a raised bed to lessen the effects of leeching from surrounding soil. Especially if your soil is extremely alkaline. To increase acidity in your soil you can add acid peat or sulfur. All amendments should be done the year before you plant.
Sulfur- When adding sulfur. your soil's acidity will increase slowly. For 50 cubic feet of sandy soil (the amount of soil in a space 10 feet by 10 feet by 6 inches), use one to two pounds of elemental sulfur to reduce the pH one point. You'll need to use about three to six pounds to get the same effect in loam soils. Elemental sulfur takes at least one year to adjust the pH. Iron sulfate reacts much faster than elemental sulfur (less than one month); however, the cost is greater. Multiply the rate of elemental sulfur needed by six to determine the required amount of iron sulfate. Aluminum sulfate is not recommended, although it can acidify soil, because high rates of this compound can be toxic to roots. Source: University of Minnesota
Acid Peat - If the pH of the soil is between 5.5 and 7.0, and the texture is sandy to sandy loam, you can easily amend the soil by mixing 4 to 6 inches of acid peat into the top 6-8in of soil. This not only increases the acid level but adds organic matter.
It's is important to monitor the soil's pH throughout the summer and fall before next year's planting to ensure the proper pH. Test and retest until the correct acid and nutrient balance has been achieved. Be sure to add organic matter like compost or peat to increase the nutrients. If your pH is 7.0 or greater, it may be impracticable to try to amend the soil as it will be a considerable amount of work to maintain the proper acidity for healthy plants.
Try to find two- or three-year-old plants from a reliable nursery. Avoid one year-old cuttings because they have a much higher mortality rate. It is always best to purchase plants that will work best in your garden. Shop around a bit and find the best cultivar that suits your growing zone. There are a few that withstand the extreme cold experienced in USDA Hardiness zone 3. The most popular cold hardy cultivars for zone 3 are Northblue, Northcountry, and Northland. Here are some facts from Cornell University about the most common cultivars on the market:
- Earliblue—hardy in Zones 5 to 7. Berries are large with light blue skin and have a soft flesh and mild flavor. The fruit does not shatter (drop easily) from the bush, and it is resistant to cracking. Plants are vigorous, productive, upright, and well shaped.
- Duke—hardy in Zones 5 to 7. This productive newer variety from New Jersey has large fruit with good flavor
- Blueray—hardy in Zones 4b to 7. Berries ripen in early midseason and are crack resistant and very large with medium–light blue skin, firm flesh, and a strong flavor and aroma. The plants are upright, spreading, and consistently productive. It overproduces (produces too much fruit, weakening the plant) unless carefully pruned.
- Patriot—hardy in Zones 4 to 7. It is partially resistant to phytophthora root rot and has excellent-tasting fruit. The plants are vigorous, productive, open, upright, and smaller than other cultivars.
- Berkeley—hardy in Zones 4 to 8. Berries are very large and light blue and have a mild flavor and firm flesh. Berries ripen in midseason, store well, resist cracking, and do not shatter from the bush. The plants are vigorous, open, spreading, and easy to grow.
- Bluecrop—hardy in Zones 4b to 7. Berries are medium large and have a light blue skin, an excellent flavor, and firm flesh. Berries shatter somewhat from the bush, but they resist cracking. The plants are vigorous, consistently productive, spreading, and drought tolerant. This is the most popular variety in the world
- Herbert—hardy in Zones 5 to 7. Berries ripen in late midseason, are very large and medium blue, and have tender flesh and a very good flavor. They resist cracking and do not shatter from the bush. The plants are consistently productive, vigorous, open, and spreading
- Darrow—hardy in Zones 5 to 7. Another variety with exceptional flavor for the home gardener.
- Jersey—hardy in Zones 4 to 8. Berries are medium sized with medium-blue skin and firm flesh. They keep well, resist cracking, and have a good flavor. The plants are vigorous, productive, erect, and easy to prune
- Coville—hardy in Zones 5 to 8. Berries are large and aromatic with medium-blue skin and a tart flavor. They do not shatter from the bush. The plants are productive and late ripening with vigorous, open, and spreading growth that is easily pruned.
- Lateblue—hardy in Zones 5 to 7. Berries are late ripening, firm, light blue, and highly flavored. The plants are productive and vigorous with erect growth. They ripen in a relatively short time, about seven days after Coville.
- Elliot—hardy in Zones 4 to 7. These productive plants bear berries that are firm, light blue, and medium sized with a good, mild flavor. They ripen very late in the season, around Labor Day
When planted correctly, bare-root plants survive as well as those grown in containers but bare root cost much less. If you do purchase container grown blueberries, before planting, prune away any roots that were twisting around the bottom of the container from being pot bound. In early spring, as soon as you get your plants, soak the roots in water for several hours and then plant them in the soil you prepared the previous year. Plant them 1in deeper than the nursery grew them no closer than 4" apart and in rows 10ft apart. Prune them back to half of their size at purchase, and remove all remaining flower buds. This will allow for the size of the roots to be balanced with the size of the bush, and allows the plant to spend it's energy to become well established and healthy for fruit production next year. Be certain to keep the plants moist as they are very sensitive to dry soil, especially in their first to years of growth.
After planted, keep the bed well weeded to allow all soil nutrients to go to the blueberries and never cultivate more then 2inches deep around the plant. Mulch well to conserve moisture and prune first year's growth so only 2 strongest canes remain. Keep one or 2 strong canes from each year until they are 8 years old and remove 9 year old canes in early spring.
Blueberries can live from 30 to 50 years so giving them a healthy start and a healthy permanent growing location is well worth the effort.