Planting celosia in a sunny garden spot is becoming a popular gardening activity as more and more gardeners are discovering these beautiful annuals. Although celosia flowers are technically perennials in the warmest regions, most gardeners must grow celosia as annual flowering plants. Choose a dwarf celosia for a low-growing border or use celosia flowers as a focal plant that may grow as tall as 3 feet high. Because celosia flowers take up to three months to flower if you plant them from seed, start your celosia flowers by planting plants in the spring.
Prepare the sunny growing area in the spring after all threat of frost is over for the spring. Cultivate the soil with the garden spade down to a depth of 4 to 6 inches. Add 2 inches of compost to the top of the soil and work this in well with the spade. Make the growing area level with the rake.
Wait until the outside temperatures will stay consistently over 60 degrees Fahrenheit and the soil temperature is over 60 F. Dig holes for each celosia plant, spacing each hole between 10 and 12 inches apart and making the holes deep enough that the plants will be at the same level as they are in the temporary containers.
Place each celosia plant into a prepared hole and place the soil firmly around the roots. Tamp the soil down with your hands to finish planting the celosia plants.
Water each newly planted celosia plant generously immediately after watering. Keep the plants evenly watered while they are establishing in the soil.
Provide water if less than 1 inch of rain falls within a one-week period. Water the celosia plants to moisten the soil.
Fertilize the celosia plants once per month with an all-purpose fertilizer. Mix the fertilizer with water according to package recommendations for the size of your growing area. Pour the fertilizer around the plants without allowing it to splash on the celosia foliage.