Blueberries are one of the most nutritious and tasty of all fruits and vegetables. The birds think so, too. But a well-established blueberry patch will produce an abundance of fruit with plenty to share.
The key to growing blueberries is to monitor the soil pH and keep it very acidic. The bushes will grow but they will not produce much fruit unless you maintain the soil pH in the range of 4.0 to 5.5. Get a soil test to determine the starting pH level. Based on that information, you can amend the soil with peat moss and other acidifying organic materials. Organic gardeners can also mix in elemental sulfur or an organic bagged fertilizer used for hollies and rhododendrons (Holly-Tone and Pro-Holly are two possibilities).
Blueberries need lots of nitrogen, so an annual application of an organic fertilizer is important. If your soil needs to be acidified to maintain a pH of 4.0 to 5.5, you may want to use a fertilizer formulated for acid-loving plants. Apply fertilizer in the spring, after the blueberry plants have blossomed. Rake back the mulch and sprinkle the fertilizer in a 12″ to 24″ band around the base of each plant. Never add fertilizer in fall, as it will stimulate new growth just before winter, which is likely to be injured by cold winter weather.
Lowbush blueberries are a fun treat when you’re hiking, but in most cases the type you plant in your garden will be a highbush variety that produce more and bigger berries. Blueberries have shallow root systems, so protect their roots with several inches of pine needles or bark mulch to hold in moisture and discourage weeds.
To maximize fruit production, you’ll want to plant two different blueberry cultivars. Planting three varieties is even better. Select a mix of early-, mid- and late-season varieties to extend the harvest season. The bushes should be planted at least 4 to 5 feet apart. They are slow-growing plants, particularly in the cooler parts of the country, but will eventually get to be 6 feet tall and 5 or 6 feet wide – or even larger. Two bushes will fit in a 3 ft. x 8 ft. or 4 ft. x 8 ft. raised bed.
Pruning is not needed for the first five years or so after planting. Begin when the bushes reach 5 to 6 feet, taking out older branches and any that are cracked, damaged or rubbing against each other. Northern gardeners should prune lightly, or you may lose your crop for several years. A mature blueberry bush will produce 5 to 15 pounds of berries per year.