People love carnations because they come in dozens of different colors and are very hardy, according to the University of Vermont. Since the first carnation was imported to North America in the 1800s, gardeners have been planting them as both edging plants and accent pieces. Several general planting tips and guidelines can help ensure your newly started carnations thrive in your landscape.
If you're starting your carnations indoors from seed, sow them in the early spring to give them time to grow several inches before transplanting them outdoors once the weather heats up. If you're direct seeding into the ground, wait until the last frost date in your area has passed.
Carnations started indoors must be hardened off before transplanting them outdoors. Once they're 4 to 5 inches tall, move them into an area that receives approximately 20 minutes of direct sunlight. Every two to three days double the amount of sunshine they receive until it matches the amount of sunlight they'll receive in their final planting spot.
Carnations thrive on rich, loamy and well-drained soil. Breakup the dirt to a depth of 1/2 foot, then mix in 4 to 5 inches of compost. The plants will grow best in slightly alkaline soil with a pH ranging between 7.0 and 7.5. A basic soil testing kit from a garden store can show you your soil pH, which can be raised or lowered with lime and phosphates. Ask your regional cooperative extension office for guidance on what soil pH amendments are commonly used in your area.
Whether you're transplanting seedlings that were started indoors or direct sowing seeds into the ground, separate the carnation plants by approximately 10 to 12 inches. Closer spacing can help your flower bed look mature faster, but you'll need to selectively remove plants as they get bigger to prevent overcrowding.