Alstroemeria, also commonly called Peruvian Lily, is a species of flowering perennials grown from underground tubers or rhizomes. The plants bloom prolifically in the spring and early summer in a wide variety of hues and petal variegation. In mild climates with good cultural care, they can bloom nearly year round. Fertilizing will help support robust blooming but only needs to be applied twice each year, making them easy to care for in this respect.
Fertilize your Alstroemeria plants twice each year, once in the spring before the flowers are set and again in the fall after the plants have died back or flowering has slowed, to recharge the tubers.
Cast the organic fertilizer of choice over the soil surrounding the plants, trying as much as possible to keep the fertilizer off of the plants themselves. Use the label-recommended dose for the amount of soil you have planted with Alstroemeria.
Water the fertilizer grains gently but thoroughly, to nestle them down into the surface soil, without displacing them.