Growing Petunia

Petunias bear showy, trumpet-shaped blooms with a single petals that flairs into a flat, five-lobed face. There are also doubled-flowered petunias with blossoms quite like Carnations or Camellies. Flowers may be ruffled, fringed, or frilled edges. Petunias come in solid or a variety of bicolor combinations, including flowers with contrasting veins, stripes, or centers. Blooms may be deep purple, lilac, pink, salmond, red, yellow, and white. Some cultivars have blossoms with sweet fragrance, which is often most evident after dark. Petunias bloom from early summer through to the first fall frost. Flowers are borne at the tips of the stems, which means that pinching increases flower production by encouraging branching.

Sow seed indoor 10 to 12 weeks before the last frost date.The seeds are dustlike, so handle them with care. They require light to germinate, so do not cover them with soil. Press the seeds into the soil, and water flats from below. Cover the seed flat with glass or plastic to maintain high humidity. Germination takes about ten days, and soil temperatures between 70 degrees F and 75 degrees F are ideal. Petunia are best grown in containers in the Tropics with some kind of covering from harsh weather.When selecting seedlings for transplanting, don't necessarily reject the smaller ones, for they are likely to produce double flowers or have the most vivid flowers.

When purchasing Petunia plants from a nursery or a garden center, look for young compact plants that have good foliage color but few flowers. Plants in full bloom are often root bound and will take longer to recover from transplant shock when set out in the garden.

Take cuttings of, or pot up healthy plants of, desirable cultivars in late or early fall. Grow them over the winter in a cool but frost-free place to supply cuttings in late winter for next season.

Pinch out the growing tips when the plants are about 6 inches tall to encourage branching and bushy growth. Pinch again after the first flush of bloom to encourage branching and more abundant flowering. If plants becomes leggy and stop blooming during the hottest part of summer, shear them back, feed them, and keep them watered to promote the development of new flowers.

A single application of compost or a slow- acting general-purpose fertilizer worked into the soil before planting will serve the basic needs of these annuals all season. However, feed plants after each pinching, and exceptional performance, give your plants supplemental, light feedings(side dressings or foliar sprays) monthly throughout the growing season.

Watering
Make sure the plants get about 1 inch of water every week from rain or by watering , but avoid overwatering, for petunias do not like soggy soil. Use a soaker hose or watering wand to apply water at ground level without wetting the flowers.

The flowers of bicolor petunias sometimes change as the season progresses. For example, a white edge may become wider or dissapear altogether , or stripes may change width. These changes occur in reaction to the plants growing conditons. When the colored areas in the flower gradually expand while white zones diminish, it is a sign that moisture and nutrients are ample and temperatures have been low. When white area expand while the colored zones shrink, it is usually because temperatures are too high, soil is too dry, and soil nutrients are depleted.

Amazing picture of pollens (above right) at close up taken by a microscope with incredible details.

During the hot summer months, Petunia plants can get leggy and stop blooming, This is because they are thermophotoperiodic, which means that both temperature and day length influence growth and flowering. When temperatures remain below 62 degrees F, the plant are compact, branch well, and flower profusely. When days are short (less than 12 hrs of light) and temperatures are between 62 degrees F and 72 degrees F, plants stop flowering or develop only a single flower per stem. When temperatures soar above 75 degrees F, regardless of the day length, the plants become leggy and stop flowering or develop only a single flower per stem.

For best results, plant petunias in spring while it's still cool, and pinch the plants to stimulate maximum branching. If temperatures are already above 70 degrees F at planting time, the flower stem will elongate rapidly and should be pinched often. In early summer, the plants can be rejuvenated by pinching again, cutting back each stem 3 to 4 inches above the soil line. This will result in a fine flower display above two weeks later. Cutting back the older stems once more in late summer as temperature start to become cooler will force more branching and heavy flowering until frost. Also keep the spent blossoms and seedpods picked off, and pinch back the side-shoots frequently.

Petunias are relatively care-free, easy-to-grow plants that are not seriously bothered by many insect pests occasionally slugs, snails, and caterpillars may chew holes in the foliage. Leaf-hoppers, which transmit aster yellows, may cause leaves that are finely mottled with yellowish or whitish spots.