Pansies grow best in full sun in moist, well-drained soil, rich in organic matter. A balanced fertilizer (10-10-10, for instance) helps them grow and bloom their best. Keeping pansies watered during dry spells helps them perform their best, especially in winter.
Pansies are heavy feeders, so failure to bloom may come from the soil being too lean. Falling behind on regular fertilization also contributes to soil infertility. Pansies that have bloomed and not been deadheaded can also fail to bloom.
Side-dressing pansies with rotted manure adds needed nitrogen and other nutrients. Likewise, using a slow-release, balanced fertilizer boosts growth and flowering. Cut back leggy plants and keep spent blooms deadheaded to encourage repeat blooming.
After several months of blooming, pansies will naturally languish when hot weather arrives. Many gardeners discard spent pansies and start over the following fall. Trying to keep them healthy and blooming throughout summer can be a frustrating task.