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Passionate Gardner-Starting Flowers from Seed—Part II: Annuals

HUERFANO- With all of the annual flowers available at your local nursery, why bother starting your own from seed?
The number one reason for me is quantity. Let’s say I want to do a mass planting of impatiens in a shady area of my garden. If I buy the 40 plants that I want, that will cost me more than $50. But, $4 will buy a packet of seeds that will grow those 40 plants. And the choices of colors are vast compared with those available at the nursery.
Another reason I like to start annuals from seed is that I can choose varieties that I cannot find in the garden centers. I am very fond of scented flowers and have noticed that, over the years, flowers like petunias get showier but less fragrant. I am partial to the spicy-sweet scents of stocks, nicotiana, heirloom petunias, sweet peas, and carnations, all often not found at garden centers. Also, if I start annuals from seeds, I have a much greater choice of unusual, cottage garden flowers to choose from.
Many flowers sold today are hybridized so that you cannot save seeds to plant for those flowers the next year. Antique or heirloom flowers, on the other hand, are open-pollinated varieties that originated over 50 years ago. Open-pollinated flowers are fertilized by insects and hummingbirds, and the resulting seeds will produce plants identical or similar to the parent plant, which makes seed-saving a worthwhile activity. One source for heirloom, old-fashioned, fragrant varieties is Select Seeds (
Just like the perennials I discussed in last week’s article, annuals also need consistent moisture, as well as variety-specific temperature and light requirements to germinate successfully. Unfortunately, most seed packets do not give you culture and growing information printed on the labels, so here I list germination requirements for some annual flower varieties.
Calendula: requires soil temperatures of 70°F. Cover these seeds lightly with germination mix, as they do not need light to germinate. Allow 8 to 10 weeks to grow this annual before setting it out in the garden. If you are planting out the last week in May, start calendula in late March. Count backward from the date you will be planting your flowers in the garden to find your seed-starting date for each variety.
• Centaurea, bachelor’s button, cornflower: 70°F, cover lightly, 7 to 8 weeks.
•Cobaea, cup and saucer vine: 70°F, cover lightly, 8 to 10 weeks.
• Dianthus, pinks, carnations: 70°F, cover lightly, 10 to 14 weeks, depending on variety.
• Geranium, standard (save money by starting your own): 75°F, cover seed, 12 weeks.
• Godetia: 70°F, cover lightly, 8 to 9 weeks.
• Impatiens: 75°F, cover seed very lightly, 8 to 9 weeks.
• Marigold: 75°F, cover, 7 to 8 weeks.
• Nasturtium: 70°F, cover, 7 to 8 weeks.
• Nicotiana: 70°F, do not cover because these seeds need light to germinate, 6 to 8 weeks.
• Petunia: 75°F, light, 10 to 11 weeks.
• Phlox: 65°F, cover, 10 to 11 weeks.
• Salvia, annual: 75°F, light, 7 to 9 weeks.
• Stock: 70°F, cover lightly, 9 to 10 weeks.
• Zinnia: 70°F, cover, 5 to 6 weeks.