Growing Blueberry in a pot

Blueberries have moderate water needs but dislike both drought and waterlogging. Their shallow roots dry out quickly, so water regularly during the growing season, especially from flowering through to harvest in July and August. In dry spells, give each bush around 10–15 litres weekly; use rainwater if your tap water is hard or alkaline, as lime will gradually raise soil pH and cause chlorosis (yellowing leaves). Reduce watering in autumn and winter, but don't let container-grown plants dry out completely. Feed in March and April with a fertiliser formulated for acid-loving plants (ericaceous feed) or a balanced slow-release granular fertiliser low in calcium. Avoid general-purpose feeds containing lime. Scatter a handful around the base of each bush and water in. Reapply in late spring if growth seems weak. Top up the mulch layer annually in spring to maintain acidity and moisture retention. Blueberries are fully hardy in zones 3a–7b and need no winter protection outdoors in temperate Europe. However, late spring frosts can damage blossom; if frost is forecast during flowering, drape fleece over bushes overnight. Birds are the main pest—net plants as berries start to colour, or you'll lose most of your crop. Aphids occasionally cluster on shoot tips in spring; squash by hand or spray with soapy water. Powdery mildew can appear in dry summers; improve air circulation through pruning and avoid overhead watering. Chlorosis (yellowing leaves with green veins) indicates the soil is not acidic enough—treat with sequestered iron and mulch with acidic material.