How to Fertilize long-flowered crocus?
Light bulb fertilizer once at emergence and again after flowering

long-flowered crocus · Crocus longiflorus
Grow in a bulb frame or alpine house in a mix of equal parts loam, leaf mould and sharp sand or grit. Water freely in the growing season and apply a low-nitrogen fertiliser monthly. Keep completely dry in summer dormancy
Light bulb fertilizer once at emergence and again after flowering