The content of this article was published by the University of Maryland Extension.
- Highbush blueberries would prefer to be planted in well-prepared soil in the ground but with proper planting and care, they can be grown in containers. Select a well-draining, large weather-proof container like a wooden barrel planter. Mature blueberries need a container at least 24 inches deep and about 24-30 inches wide. When planting smaller shrubs, start with a smaller container and repot as it grows. Repot in late summer - early fall so roots have enough time to grow before winter.
- Don't expect to harvest blueberries the first year. If you purchase 1-year old plants, remove the flowers when they appear in spring so plants can concentrate their energy on root growth. It takes about 5 years for plants to produce a full crop of berries. Planting another variety in a separate container will encourage cross-pollination as long as they bloom at the same time. This will increase yield.
- Use a 50-50 mix of potting soil and peat moss as your planting media. Wet it thoroughly before placing it in the container. If the shrub is pot bound gently tease the roots to encourage root expansion into the potting media. Place the blueberry into the potting media and plant it the same depth as it was in its container. Then water well.
- Place containers in full sun, but protection from late afternoon sun may be necessary.
- Avoid fertilizers containing nitrates or chlorides. Blueberries need an acidic based fertilizer. Fertilize containers in early spring before leaves expand.
- Blueberries are very sensitive to dry conditions. Keep the containers watered and soil evenly moist. If containers are placed on hard surfaces, place them on top of bricks for drainage.
- Cover bushes with bird netting or floating row cover when the berries just begin to ripen.
- During the winter months (December-March) containers need to be in a sheltered location, protected from winter winds.