The Ballon Flower (Platycodon grandiflorus) is suitable for sunny to semi-shaded places.
The soil should be well drained and can be enriched with some compost and mineral shares, such as sand or fine gravel.
If Platycodon grandiflorus ist in growth or bloom, keep the garden soil evenly moist but not wet. How often you have to water depends on the location. In full sun the ground drains faster than at a semi-shaded place. When the temperatures are above 25 °c i water mine every 2-3 days.
As fertilizer i use pond water. In spring the soil can be covered with some compost.
Platycodon grandiflorus is hardy in zones 3 to 8 and showing up very late in spring.