AAS Winning Zinnias

Diversity

One of the reasons for the popularity of the zinnia is its diversity.

• Zinnias have a variety of flower forms—single, semi-double, or double.
• Zinnias also come in an amazing array of colors. Most are solid, but some are bicolored with contrasting colors on each petal. You’ll find yellow, orange, cherry, pink, purple, scarlet, and white, as well as fashionable chartreuse—just about every color, in fact, but blue.
• Zinnias have growing habits to suit every need. Tall, 3- to 4-foot varieties are best for the middle or rear of a border or in a cutting garden. Dwarf plants grow 8 to 14 inches tall and do well in pots as well as at the front of a garden.

Growing From Seed is Easy

Starting Zinnia seeds indoor

• For earlier flowers, and in colder zones, you may want to give the plants a head start by sowing indoors.
• Sow the seeds indoors about 4 to 6 weeks before the average last frost date in your area. In frost-free areas, count back from the date when you’ll be planting tomatoes, impatiens, and other warm-weather annuals in the garden.
• Fill a shallow container or individual peat pots with a commercial seed-starting mix. Moisten the mix and let it drain.
• Sow the seeds and cover lightly with a layer of mix then spritz it with enough water to moisten slightly.
• Cover the flat with a sheet of plastic to keep the mix from drying out while the seeds are germinating. Set it in a bright location or under grow lights. Keep the growing medium at about 75º – 80º F (24º – 26 ºC) by placing it on a heat mat or warm surface.
• Seedlings should emerge in about a week. Remove the plastic cover and keep the mix evenly moist—not soggy—by watering the flat from the bottom.
• When the seedlings have at least two sets of true leaves, transplant into 2¼-inch or larger pots. Provide as much sunlight as possible so the plants don’t get leggy from stretching.

Sow seeds directly in the garden

• Wait to sow until all danger of frost has passed and the air and soil are warm. Amend the soil by digging in a 2-inch layer of compost before planting for better drainage and improved fertility.
•  It’s easiest to sow the seeds in rows, but you can also sow them in groups. Cover smaller seeds (of Z. angustifolia, for instance) with about ¼ inch of soil, and larger seeds with ½ inch.
• Space seeds a little more closely than you’ll want the eventual plants.
• Keep the soil moist until the seeds germinate.
• When the seedlings have two pairs of leaves, thin them to the correct spacing. If you carefully pull out the unwanted seedlings, you can transplant them to other parts of the garden. Otherwise, simply snip them at ground level.

Caring for Zinnias

• Zinnias grow best in full sun, which means six or more hours of direct sun daily. In desert locales and zones 9 to 11, choose a site that gets some shade at midday and in the late afternoon.
• They prefer moist but well-draining soil—whether planted in the ground or in containers—so it’s important to prepare the planting bed by working in organic material, such as compost, especially if the soil is sandy, or heavy clay.
• One of the nicest aspects of zinnias is that a part of their maintenance requirements is cutting the blooms frequently to keep the plants compact and bushy and producing more flowers. Otherwise, planted in the right site in good soil, they are fairly carefree.
• Water regularly if it doesn’t rain. Even though zinnias love hot weather they do need moisture. Remember to check the soil in containers daily during hot summer weather and water if it is dry to a depth of 2 inches or more. In extremely hot, dry weather, you may need to water twice a day. Water at the base of the plants, rather than sprinkling the foliage.
• Zinnias aren’t heavy feeders but fertilize plantings at least twice during the growing season. Use a balanced granular or water-soluble fertilizer—for instance, one with 20-20-20 on the label—or mix a slow-release or organic fertilizer into the soil when you plant. Always follow label directions for amounts. Mix a timed-release or organic fertilizer into the soilless mix when you plant zinnias in containers or feed them once a month with a water-soluble fertilizer or diluted fish emulsion. Be sure to dilute to the strength recommended on the label for containers.