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Annual flowers from seed: sowing, colour, containers and borders
Annuals complete their life in one season, so a packet of seed gives a full season of flowers. Hardy annuals tolerate frost and are sown early or in autumn; half-hardy and tender annuals wait for the last frost or start indoors.
Hardy, half-hardy and tender
Hardy annuals (calendula, poppy, cornflower, larkspur, sweet pea, nigella) can go outdoors before the last frost, and some sow in autumn. Half-hardy and tender annuals (zinnia, marigold, cosmos, petunia, impatiens, celosia) are damaged by frost, so start them indoors a few weeks ahead or sow when the soil is warm. The calendar splits plants this way from your last-frost date.
Choosing by job
Borders and height: sunflower, cosmos, larkspur. Edging and containers: alyssum, marigold, pansy, nasturtium. Fences, pergolas, arbors and trellises: sweet pea, morning glory, nasturtium. Pollinators: zinnia, cosmos, calendula, sunflower, borage. Fragrance: sweet pea, nicotiana, alyssum. Dry or poor soil: calendula, cosmos, nasturtium, gaillardia. Shade: impatiens, nicotiana, pansy. Cut flowers: see the cut-flowers guide.
Easy wins for beginners
Zinnia, marigold, cosmos, sunflower, nasturtium and calendula germinate in a week or so, grow fast and flower within a few months. Sow them where they will flower or in pots and plant out when frost has passed.
Pots, balconies and decks
Choose compact varieties and use a good potting mix. Containers dry out faster than beds, so water regularly and feed during bloom. Pinch back young plants to make them branch.
Heat, cold and drought
Heat-tolerant: zinnia, cosmos, gomphrena, celosia. Cold-tolerant: pansy, calendula, sweet pea, larkspur. Drought-tolerant once established: gaillardia, cosmos, nasturtium, strawflower.
Plants in this guide
| Plant | Germination temp | Depth | Days | Light | Before sowing |
|---|---|---|---|---|---|
| Zinnia Zinnia elegans | 70 to 85°F | ¼ in (6 mm) | 3 to 7 | Cover | Nothing needed |
| Marigold Tagetes spp. | 75 to 80°F | ¼ in (6 mm) | 3 to 14 | Either | Nothing needed |
| Cosmos Cosmos bipinnatus | 68 to 72°F | covered lightly | 5 to 10 | Cover | Nothing needed |
| Sunflower Helianthus annuus | 70 to 75°F | ½ in (12 mm) | 5 to 14 | Cover | Nothing needed |
| Snapdragon Antirrhinum majus | 70 to 75°F | surface | 7 to 14 | Needs light | Nothing needed |
| Petunia Petunia × hybrida | 72 to 77°F | surface | 6 to 10 | Needs light | Nothing needed |
| Nasturtium Tropaeolum majus | 60 to 70°F | ½ to 1 in (12 to 25 mm) | 7 to 14 | Cover | Nothing needed |
| Impatiens Impatiens walleriana | 70 to 75°F | surface | 10 to 14 | Needs light | Nothing needed |
| China aster Callistephus chinensis | 70 to 72°F | covered lightly | 7 to 14 | Either | Nothing needed |
| Calendula (pot marigold) Calendula officinalis | 70 to 70°F | ¼ in (6 mm) | 7 to 14 | Either | Nothing needed |
| Poppy Papaver and Eschscholzia spp. | 60 to 75°F | surface | 7 to 21 | Needs light | Nothing needed |
| Pansy and viola Viola spp. | 62 to 75°F | ¼ in (6 mm) | 4 to 15 | Either | Nothing needed |
| Phlox (annual) Phlox drummondii | 60 to 65°F | ¼ in (6 mm) | 5 to 15 | Either | Nothing needed |
| Verbena (tall) Verbena bonariensis | 60 to 86°F | see page | 14 to 28 | Nothing needed | |
| Larkspur Consolida ajacis | 55 to 55°F | ¼ in (6 mm) | 14 to 21 | Cover | Nothing needed |
| Sweet pea Lathyrus odoratus | 55 to 65°F | ¼ to ½ in (6 to 12 mm) | 14 to 21 | Cover | Nothing needed |
| Cornflower Centaurea cyanus | 60 to 65°F | see page | 7 to 14 | Nothing needed | |
| Nigella (love-in-a-mist) Nigella damascena | 60 to 65°F | see page | 10 to 14 | Nothing needed | |
| Celosia Celosia spp. | 70 to 80°F | covered very lightly | 8 to 14 | Needs light | Nothing needed |
| Gomphrena (globe amaranth) Gomphrena globosa | 70 to 78°F | covered lightly | 5 to 14 | Either | Nothing needed |
| Statice Limonium sinuatum | 70 to 70°F | just enough to hold the seed | 5 to 14 | Needs light | Nothing needed |
| Strawflower Helichrysum bracteatum | 70 to 75°F | surface | 7 to 10 | Needs light | Nothing needed |
| Nicotiana (flowering tobacco) Nicotiana spp. | 72 to 78°F | surface or lightly pressed in | 7 to 14 | Needs light | Nothing needed |
| Ageratum Ageratum houstonianum | 70 to 80°F | surface | 7 to 10 | Needs light | Nothing needed |
| Sweet alyssum Lobularia maritima | 65 to 70°F | see page | 8 to 10 | Nothing needed | |
| Morning glory Ipomoea purpurea | see page | about ½ in (12 mm) | varies | Cover | Treat seed |