When to plant blueberries in zone 5a
In zone 5a, the average last spring frost is May 15 and the first fall frost is Oct 1. Here is blueberries's whole year, counted from those dates.
Blueberries need acidic, well-drained soil. Clemson says to pick another site if the pH is above 6.0, and to apply sulfur only when a test shows the pH is below 6.0 but above 5.5, at least three months before planting. A USDA small-farm note puts the optimum near 4.8–5.2, with 5.5 still acceptable. Test the soil and amend the year before you plant.
The calendar marks the average last spring frost. The USDA note says spring planting starts once severe-frost danger has passed. Clemson plants bare-root bushes in late winter as soon as the soil can be worked, which can be earlier than that frost date, and plants potted bushes in fall on sandy soil. Set each plant at the same depth it grew in the nursery or pot. No single week-before-frost number was published for every zone, so the earlier bare-root window is described here rather than given its own date.
Clemson spaces southern highbush 4–5 feet apart in the row and rabbiteye 6 feet apart. The USDA note says in-row spacing is commonly 4 or 6 feet. Minnesota Extension uses about 3 feet and plants in late April or early May, which is tighter than the spacing on this page. Plant at least two cultivars. Rabbiteye needs a second variety for pollination. Remove flower buds the first and second years so the bush grows wood and roots.
Clemson says fruit ripens over about two months after bloom. With good care, a bush may give about half a pound in the third year. The USDA note says plantings are not harvested until the third or fourth growing season.