How to Grow Petunias from Seed
Petunias are a dependable, sun-loving annual that will bloom brightly all season. Available in a variety of colors, with single or double blooms, petunias require only sunshine and sufficient watering to thrive. Instead of buying plants from a nursery, read on to learn how to grow petunias from seed.
Seed Germination
Six to eight weeks before you expect the last frost, scatter seeds lightly on the surface of a planting tray filled with potting soil. Don’t distribute the seeds too closely together, as seeds need sufficient light and air circulation. Press seeds lightly into the soil and moisten with a mister. Cover with plastic wrap, and place the tray in a warm location that is out of direct sunlight. Under favorable conditions, seedlings may emerge in three or four days.
Transplanting Seedlings
Remove the plastic wrap when seedlings have emerged, and allow the soil to dry out slightly between waterings. Watch for wilting, as adequate moisture is critical at this stage. When the seedlings have developed two leaves, transplant them to individual containers and keep the temperature at about 65 degrees F. Water every two weeks with a liquid fertilizer. Bring seedlings outside on warm spring days, but take them back inside at night to avoid freezing.
Transferring Plants Outside
Plant after the danger of frost has passed when the soil temperature has warmed to at least 60 degrees F. Remove carefully from containers, taking care to leave roots undisturbed, and plant approximately 12 inches apart. Water well to avoid wilting.
Caring for Petunias
In early or mid-July, begin the application of liquid fertilizer and reapply every two weeks. Water deeply when the soil appears dry. Adding mulch to flower beds will reduce the need for water. Hanging baskets and pots will require more water than petunias in beds. Pinch dead flowers to encourage increased bloom production.
Resources – How to Grow Petunias from Seed
The University of Minnesota Extension – Growing Petunias
Iowas State University – Extension and Outreach – Horticulture and Home Pest News – How to Start Petunias Indoors from Seed
