Germination requirements (light and temperature) vary among the different flowers and vegetables. The various crops also differ in the length of time from seed sowing until the seedlings are transplanted outdoors.
The following chart provides germination information for many of the commonly grown annual flowers.
| Annual | Germination Temperature (Fahrenheit) |
Lighting | Days to Germination |
Weeks Sowing to Planting |
|---|---|---|---|---|
| Ageratum (Ageratum houstonianum) | 70-75 | L | 7-10 | 8 |
| Snapdragon (Antirrhinum majus) | 70 | L | 7-14 | 8-10 |
| Wax Begonia (Begonia x semperflorens-cultorum) | 70-75 | L | 14 | 10-12 |
| Annual Aster (Callistephus chinensis) | 70 | L-D | 7-10 | 6-8 |
| Vinca (Cathranthus roseus) | 70-75 | L-D | 14 | 10 |
| Cockscomb (Cleosia spp.) | 70-75 | D | 7-10 | 6-7 |
| Bachelor's Button (Centaurea cyanus) | 65-70 | L-D | 7-14 | 8 |
| Cosmos (Cosmos spp.) | 70 | D | 5-7 | 4-6 |
| Lisianthus (Eustoma grandiflorum) | 75 | L | 10-14 | 14 |
| Globe Amaranth (Gomphrena globosa) | 70 | L-D | 14 | 7-8 |
| Sunflower* (Helianthus annuus) | 70 | D | 5-7 | 3-4 |
| Strawflower (Helichrysum bracteatum) | 70-75 | L-D | 7-10 | 6-8 |
| Impatiens (Impatiens wallerana) | 70-75 | L | 10-14 | 8-10 |
| Annual Statice (Limonium sinuatum) | 70 | L-D | 7-10 | 8-10 |
| Melampodium (Melampodium paludosum) | 65-70 | L-D | 7-10 | 7 |
| Four-O'Clock (Mirabilis jalapa) | 70 | D | 5-7 | 6-8 |
| Flowering Tobacco (Nicotiana alata) | 70-75 | L | 10-14 | 8 |
| Geranium (Pelargonium x hortorum) | 70-75 | D | 7-21 | 12 |
| Petunia (Petunia x hybrida) | 75 | L | 7-10 | 8-10 |
| Moss Rose (Portulaca grandiflora) | 75 | L | 7-10 | 10 |
| Black-Eyed Susan (Rudbeckia spp.) | 70 | L-D | 7-14 | 10 |
| Red Salvia (Salvia splendens) | 70-75 | L | 10-14 | 8 |
| Mealycup Sage (Salvia farinacea) | 70-75 | L | 10-14 | 8-9 |
| Creeping Zinnia (Sanvitalia procumbens) | 70 | D | 7-10 | 6-7 |
| Coleus (Solenostemon spp.) | 70-75 | L | 10-14 | 8-10 |
| Dahlberg Daisy (Thymophylla tenuiloba) | 65-70 | L | 14 | 8 |
| Nasturtium* (Tropaeolum majus) | 65-70 | D | 10-14 | 5-6 |
| Zinnia (Zinnia elegans) | 70 | D | 5-7 | 5 |
*Sunflowers and nasturtiums do not transplant well. Both should be seeded directly into peat pots.
Light conditions during germination are critical for many annual flowers. The seeds of some plant species require light for germination. (In the table above, annuals that require light for germination are designated with the letter L in the lighting column.) After sowing these seeds, lightly press them into the germination medium, but do not cover them. The seeds of other flowers require darkness (D) and should be covered with the germination medium. Finally, those designated L-D should be lightly covered, leaving the seeds as close to the soil surface as possible.
Category: Horticulture
Authors: Richard Jauron
Iowa State University
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach.
Town & Country Gardening 
I prefer perennials. I’ve been looking at the County Extension plant sales today. Here in the Great Lakes they sell beach grass…which pleases me no end.
LikeLike
Reblogged this on Homestead & Homespun.
LikeLike
60F and sunny on the Equinox yesterday. Tempting to start planting, but March is too early for our mountains. Restrain, restraint, restraint. We have the seeds lined up and ready to go. For now, cutting and splitting next year’s wood, cleaning out the garden beds, and enjoy the daffodils, snow drops, etc. are our pleasure. – Oscar
LikeLiked by 1 person
Thank you very informative 🙂
LikeLike
Not much germinating here yet! Can’t wait though (but I guess I’ll have to).
LikeLike
Nice chart!
LikeLike