Successful Blueberry Tips and Tricks
The main thing to know with blueberries is to transplant them right in the first place, keep the soil fairly acid over the years, and be patient. They take a few seasons to get into full swing.
Site and Soil
Blueberries must be planted where they have full sunlight most or part of the day and in acid soils (pH 4.5-5.5) that are well grained, porous and high in organic matter. They are shallow-rooted plants and must be irrigated, heavily mulched, or planted in soil with a high water table. However, they can not tolerate standing in water.
If the soil is not acid enough, it can be acidified in one of these three ways:
Mix equal parts of acid peat and garden soil. This should be done at least six months before planting (in September of the spring before you plan to plant blueberries).
Add sulfur at the rate of one pound per 100 square feet. The acid soil can then be maintained by annually adding acid-forming fertilizer such as ammonium sulfate.
Mulch 2 or 3 inches deep with pine bark, pine straw or sawdust. Mulch will also help control weeds and retain moisture.
Please have your soil tested by the extension office and use only one of the three methods above to acidify it to the proper levels.
Planting
Early spring planting is recommended (after last frost, of course). Set the plants four feet apart in rows six feet apart. Blueberries have a very shallow root system. Plant at the same level as they were growing in their nursery pots. The plants will have a definite line that shows you the right depth. Firm soil around the plants, mulch and water to set.
To improve the productivity of blueberries, at least two varieties should be planted, because blueberries require cross-pollination between varieties.
Fertilizing
Fertilizing is recommended in early spring once the plants are established. Apply a balanced fertilizer such as 10-10-10. Also, an Azalea-Rhododendron fertilizer is good for blueberries.
When using mulch a high nitrogen fertilizer is necessary since decomposing mulch removes the nitrogen from the soil. In spring just before the buds break, apply about 2 ounces (1/4 cup) of ammonium sulfate under the branches around each plant.
Pruning
Pruning can be done anytime from leaf fall until growth begins again in the spring. From the time of planting until the end of the third growing season, remove only the dead branches, injured branches, and branches that are too close to the ground. As the bushes come into bearing (usually in the fourth year), regular pruning is necessary. Regular pruning consists of removing dead and injured branches and trimming back bushy twigs.
Pest Control
Birds are attracted to blueberries. Covering with plastic netting supported by a light framework is the best bird deterrent.
Insect pests seldom become a problem. Removing over ripe fruit and diseased branches help keep insects away. If you find you have creepy crawlies, call your favorite greenhouse or your local extension service for help identifying and dealing with the problem.
Winter Protection
In those lucky parts of the United States which experience severe winters (like Northern Minnesota, for instance!), winter protection is required. A covering of straw in the fall about six inches deep helps reduce plant injury. Some gardeners use a fence of wire to contain the straw. Apply the mulch after plants have been subject to a few good frosts, and don’t forget to rake it away and compost properly in the spring.