You can grow petunias from seeds, but it is easier to grow them from transplants. If you are going to grow from seeds, start them indoors 10 to 12 weeks before you want to set them outside. Petunia seeds are very small and needs lots of light in order to germinate. Remember to water them. When the plants have three leaves, you can plant them outside.
It’s best to buy transplants and plant them in light, well-drained soil in full sun after the last spring frost. Petunias can grow in partial shade, but they will have fewer flowers. It’s better if the plants have shelter from the wind.
Space the plants about 1 foot apart.
If you’re planting petunias in containers, use a soil-less mix. [.]
Petunias for Winter-Bloom
Before you take cuttings of your petunia, make sure the plant has been well-fed and watered. Cut stems approximately 3 inches in length. Then remove all leaves from the lower half of the stem. Remove all flowers, buds, and seed-pods, too. Otherwise, the cutting will focus its energy on flowering and seed-ripening — not growing roots. Now grab a perfectly clean, 6-inch-diameter clay pot. And plunge it into the soil, to a depth that approximates the length of your cutting. Take a cutting, and lower it into a hole, right up to its lower leaves. Then press firmly around the stem, so that soil and cutting make good contact. Now gently water the cuttings, until excess drips through the drainage hole. Keep the stems moist, but not saturated, throughout the rooting process. [.]
Ever wondered how to grow petunias that will be the envy of your neighborhood or garden club? Here are 10 tips from Wave Petunias to help you grow perfect petunias:
If you can, plant your petunias early enough in the season to enable them to establish strong root systems before high temperatures set in. The more established the plant, the more heat tolerant it is.
When planting petunias, maintain the same plant depth as the original pot or pack. Space spreading petunias, such as Wave or Easy Wave Petunias, 12 to 24 inches apart in garden beds to allow room to grow.
Plant petunias in a sunny location. They need at least six hours of direct sunlight to keep plants blooming and looking their best all season long.
Petunias are heavy “feeders.” Apply a liquid fertilizer every 10 to 14 days, or use a combination of a liquid and a slow-release fertilizer.
Don’t let your petunias dry out. They need plenty of water, but keep in mind that the soil in beds and containers must be well drained. If possible, water your plants in the morning so the foliage dries before evening.
Rotate your garden beds every year to avoid planting petunias in the same spot. If you want to give your garden beds a break, Wave works well in containers, baskets and window boxes as well.
For lush, full container displays, place three plants in a 10- to 12-inch (25 to 30 cm) container, hanging basket or patio planter. Larger containers will require additional plants for an attractive, proportioned display.
Try planting spreading petunias in a moss-lined hanging basket. The moss will allow you to place an additional 10 plants on the side of the basket for a fast, beautiful cascading look.
Some petunias can be cut back occasionally to encourage growth and rejuvenate plants. Check the directions on the individual plant to see if cutting it back will help the plant grow fuller.[.]
Remove faded/dead flowers to prolong blooming.