How to Grow Carnations in a Container

Fill a medium-size container with a well-drained, fertile potting soil. Sow a carnation seed ½ inch deep in the soil and water lightly. Place the container in a location that receives four to five hours of full sunlight each day. Keep the soil slightly moist and germination will occur in about six weeks.

Maintain a constant temperature of 60 to 65 degrees Fahrenheit at all times for the best flower and foliage development. Keep a thermometer near the plant to ensure the temperature does not rise above 65 degrees Fahrenheit, or permanent damage may occur.

Water container-grown carnations once per week to keep the soil consistently moist. Do not over-water or the foliage will yellow and possibly drop. Apply water directly to the soil to avoid moistening the leaves, as wet foliage is more vulnerable to pests and disease.

Feed carnations once every six to eight weeks using a 20-10-20 NPK fertilizer to provide necessary nutrition. Read the instructions on the package for proper dosage information. Water lightly after fertilizing to prevent root burn and distribute the nutrients throughout the soil.

Harvest blossoms after flowering has begun. Prune the carnation plant to about 1 inch above the soil level after flowering ends to rejuvenate the plant and prepare it for the next blooming season.

Repot carnations during early spring after two to three years of growth, or whenever the plants have outgrown their current growing container. Increase the size of the container by 3 to 5 inches and provide a fresh growing medium to ease the shock of transplant.