Blueberries need a suitable acidic root environment and enough light. Check the cultivar, container size and local climate before planning for fruit.
Choose blueberries for the climate and space
Select a named cultivar with suitable chilling needs and mature size. Check whether a compatible flowering partner will improve cropping. A small nursery plant is not evidence that one shallow balcony pot will support it indefinitely.
Provide an acidic root environment
Use suitable ericaceous compost and check the water available. Blueberries need acidic conditions, commonly around pH 4.5 to 5.5. Avoid unmeasured household acids or repeated supplements without understanding the growing medium.
Keep moisture steady with drainage
Check the root ball regularly during active growth and fruit development, especially in wind. Water when needed and let surplus escape. A dry surface can hide wet material below, while a small original root ball may dry inside moist new compost.
Plan ongoing maintenance
Give useful light, inspect root congestion and prune according to the plant's age and fruiting growth. Protect fruit appropriately where birds are a problem. More fertilizer cannot guarantee a crop where pollination, climate requirements or root conditions are unsuitable.
Related reading
Blueberry Types: Climate, Size and Cultivar Choice