Seeds are in a dormant state until the right conditions occur which triggers the end of dormancy. There are a number of critical factors that determine when a seed will germinate including moisture, oxygen and the right soil temperature. Some seeds also require a period of cold, known as cold stratification. This mimics the normal winter a seed would usually experience before germinating once temperatures warm up in spring.
We recommend gardeners purchase a soil temperature thermometer to check soil temperature before sowing seeds. These are available from most nurseries or online.
Celsius |
Fahrenheit |
Stratification? |
|
African daisy (Arctotis stoechadifolia) | 18 – 21 | 65 – 70 | No |
African daisy (Osteospermum spp.) | 21 – 24 | 70 – 75 | No |
Alyssum (Lobularia maritima) | 12 – 23 | 55 – 75 | No |
Amethist flower (Browallia spp.) | 18 – 21 | 65 – 70 | No |
Aster (Aster spp.) | 18 – 23 | 65 – 75 | No |
Baby’s breath (Gypsophila spp.) | 15 – 18 | 60 – 65 | No |
Balloon flower (Platycodon grandiflorus) | 16 – 20 | 60 – 68 | No |
Bear’s breeches (Acanthus mollis) | 18 – 21 | 65 – 70 | No |
Bee balm (Monarda didyma) | 16 – 21 | 60 – 70 | No |
Begonia (Begonia spp.) | 18 – 21 | 65 – 70 | No |
Bellflower (Campanula spp.) | 21 – 23 | 70 – 75 | Yes |
Bells-of-Ireland (Moluccella laevis) | 13 – 18 | 55 – 64 | Yes |
Black-eyed Susan (Rudbeckia hirta) | 18 – 21 | 65 – 70 | Yes |
Bleeding heart (Dicentra spectabilis) | 4 – 12 | 40 – 55 | Yes |
Boltonia (Boltonia spp.) | 18 – 21 | 65 – 70 | No |
Borage (Borago officinalis) | 18 – 29 | 65 – 85 | No |
Bugle flower (Ajuga spp.) | 10 – 15 | 50 – 60 | No |
Bugloss (Anchusa capensis) | 18 – 21 | 65 – 70 | No |
Butter daisy (Melampodium paludosum) |
18 – 21 | 65 – 70 | No |
Butterfly flower (Schizanthus spp.) | 18 – 22 | 65 – 71 | No |
Butterfly weed (Asclepias tuberosa) | 18 – 24 | 65 – 75 | Yes |
Calendula (Calendula officinalis) | 18 – 21 | 65 – 70 | No |
Californian poppy (Eschscholzia californica) | 12 – 21 | 55 – 70 | No |
Candytuft (Iberis spp.) | 23 – 29 | 75 – 85 | No |
Canterbury bells (Campanula medium) | 18 – 21 | 65 – 70 | Yes |
Cape jewels (Nemesia strumosa) | 13 – 18 | 55 – 65 | No |
Carnation (Dianthus spp.) | 15 – 21 | 60 – 70 | No |
Catnip/catmint (Nepeta spp.) | 18 – 21 | 65 – 70 | No |
Chamomile (Matricaria chamomilla) | 18 – 21 | 65 – 70 | Yes |
Chilean bellflower (Nolana paradoxa) | 20 – 22 | 68 – 72 | No |
Chinese aster (Callistephus chinensis) | 20 – 23 | 68 – 73 | No |
Chinese forget-me-not (Cynoglossum amabile) | 18 – 20 | 65 – 68 | No |
Chinese lantern (Physalis alkekengi) | 16 – 21 | 60 – 70 | No |
Chrysanthemum (Chrysanthemum spp.) | 18 – 23 | 65 – 75 | No |
Clematis (Clematis spp.) | 20 – 22 | 68 – 73 | Yes |
Cliquefoil (Potentilla spp.) | 19-21 | 67-70 | No |
Cohosh (Cimicifuga spp.) | 18 – 21 | 65 – 70 | No |
Columbine (Aquilegia spp.) | 10 – 12 | 50 – 55 | Yes |
Common rockrose (Helianthemum nummularium) | 21 – 24 | 70 – 75 | No |
Common sneezeweed (Helenium autumnale) | 19 – 22 | 65 – 73 | No |
Coral bell (Heuchera spp.) | 18 – 21 | 65 – 70 | No |
Corncockle (Agrostemma githago) | 15 – 21 | 60 – 70 | No |
Cornflower (Centaurea cyanus) | 15 – 21 | 60 – 70 | No |
Cosmos (Cosmos bipinnatus) | 21 – 25 | 70 – 77 | No |
Cup and saucer vine (Cobaea scandens) | 21 – 23 | 70 – 75 | No |
Cupflower (Nierembergia spp.) | 21 – 23 | 70 – 75 | No |
Cupid’s bow (Achimenes spp.) | 21 – 23 | 70 – 75 | No |
Cupid’s dart (Catananche caerulea) | 20 – 23 | 68 – 75 | No |
Cyclamen (Cyclamen spp.) | 18 – 20 | 65 – 68 | No |
Dahlberg daisy (Dyssodia tenuiloba) | 18 – 21 | 65 – 70 | No |
Dahlia (Dahlia spp.) | 21 – 23 | 70 – 75 | No |
Delphinium (Delphinium elatum) | 15 – 20 | 59 – 68 | Yes |
Echinacea (Echinacea spp.) | 18 – 21 | 65 – 70 | Yes |
Edeiweiss (Leontopodium alpinum) | 18 – 21 | 65 – 70 | Yes |
English daisy (Bellis perennis) | 18 – 21 | 65 – 70 | No |
Evening primrose (Oenothera spp.) | 21 – 26 | 70 – 80 | No |
Everlasting (Helichrysum bracteatum) | 21 – 24 | 70 – 75 | No |
False sunflower (Heliopsis spp.) | 21 – 23 | 70 – 73 | No |
Fan flower (Scaevola aemula) | 20 – 22 | 68 – 71 | No |
Firecracker flower (Crossandra infundibuliformis) | 21 – 27 | 70 – 80 | No |
Flax (Linum usitatissimum) | 18 – 21 | 65 – 70 | No |
Fleabane (Erigeron spp.) | 18 – 21 | 65 – 70 | No |
Floss flower (Ageratum houstonianum) | 24 – 29 | 75 – 85 | No |
Forget-me-not (Myosotis spp.) | 18 – 21 | 65 – 70 | No |
Foxglove (Digitalis spp.) | 15 – 18 | 60 – 65 | No |
Garden heliotrope (Heliotropium spp.) | 18 – 21 | 65 – 70 | No |
Gay feather (Liatris spp.) | 18 – 21 | 65 – 70 | Yes |
Gazania (Gazania spp.) | 15 – 18 | 60 – 65 | No |
Gerbera (Gerbera spp.) | 21 – 23 | 70 – 73 | No |
Geum (Geum spp.) | 18 – 21 | 65 – 70 | No |
Globeflower (Trollius spp.) | 18 – 21 | 65 – 70 | Yes |
Glory of the snow (Chionodoxa spp.) | 10 – 15 | 50 – 59 | Yes |
Gloxinia (Sinningia speciosa) | 19 – 21 | 66 – 70 | No |
Goldencup (Hunnemannia fumariifolia) | 19 – 21 | 66 – 70 | No |
Goldenrod (Solidago spp.) | 20 – 22 | 68 – 71 | Yes |
Goldentuft (Aurinia saxatilis) | 15 – 21 | 59 – 70 | No |
Hellebore (Helleborus spp.) | 18 – 21 | 65 – 70 | Yes |
Hibiscus (Hibiscus spp.) | 21 – 26 | 70 – 75 | No |
Hollyhock (Alcea rosea) | 15 – 21 | 60 – 70 | Yes |
Iceland poppy (Papaver nudicaule) | 18 – 24 | 65 – 75 | Yes |
Impatiens (Impatiens spp.) | 21 – 23 | 70 – 73 | No |
Jacob’s ladder (Polemonium spp.) | 18 – 21 | 65 – 70 | No |
Laceflower (Trachymene coerulea) | 18 – 21 | 65 – 70 | No |
Ladys purse (Calceolaria spp.) | 21 – 23 | 70 – 73 | No |
Larkspur (Consolida ambigua) | 10 – 12 | 50 – 55 | Yes |
Lavender (Lavandula spp.) | 18 – 21 | 65 – 70 | No |
Leopard plant (Ligularia spp.) | 18 – 21 | 65 – 70 | No |
Linaria (Linaria spp.) | 12 – 18 | 55 – 65 | Yes |
Lisianthus (Eustoma grandiflorum) | 22 – 23 | 72 – 73 | No |
Livingstone daisy (Dorotheanthus bellidiformis) |
18 – 24 | 65 – 78 | No |
Lobelia (Lobelia spp.) | 18 – 23 | 65 – 73 | No |
Love-lies-bleeding (Amaranthus caudatus) | 20 – 28 | 68 – 82 | No |
Lupine (Lupinus spp.) | 12 – 21 | 55 – 70 | Yes |
Madagascar periwinkle (Catharanthus roseus) |
24 – 27 | 75 – 80 | No |
Marigold (Tagetes spp.) | 21 – 23 | 70 – 73 | No |
Marshmallow plant (Althaea officinalis) | 15 – 21 | 60 – 70 | Yes |
Mexican creeping zinnia (Sanvitali procumbens) | 18 – 21 | 65 – 70 | No |
Mignonette (Reseda odorata) | 12 – 14 | 53 – 57 | No |
Monkey flowers (Mimulus spp.) | 15 – 21 | 60 – 70 | No |
Monk’s hood (Aconitum spp.) | 12 – 15 | 55 – 60 | Yes |
Morning glory (Convolvulus spp.) |
20 – 21 | 68 – 70 | No |
Nasturtium (Tropaeolum majus) | 15 – 18 | 60 – 65 | No |
Nemesia (Nemesia spp.) | 12 – 18 | 55 – 65 | No |
Nemophila (Nemophila spp.) | 12 – 15 | 55 – 60 | No |
Nigella (Nigella damascena) | 15 – 18 | 60 – 65 | No |
Obedient plant (Physostegia virginiana) | 18 – 21 | 65 – 70 | No |
Pansy (Viola tricolor var. hortensis) | 15 – 23 | 60 – 73 | No |
Pearly everlasting (Anaphalis margaritacea) | 18 – 21 | 65 – 70 | No |
Persian violet (Exacum affine) | 21 – 24 | 70 – 78 | No |
Petunia (Petunia spp.) | 18 – 23 | 65 – 73 | No |
Phlox (Phlox spp.) | 15 – 18 | 60 – 65 | No |
Poppy (Papaver spp.) | 15 – 20 | 60 – 68 | Yes |
Portulaca (Portulaca spp.) | 21 – 26 | 70 – 80 | No |
Pride of Madeira (Echium candicans) | 15 – 20 | 60 – 68 | No |
Primrose (Primula spp.) | 15 – 18 | 60 – 65 | Yes |
Purple rock cress (Aubrieta deltoidea) | 18 – 21 | 65 – 70 | No |
Queen Anne’s lace (Daucus carota) | 16 – 18 | 60 – 65 | No |
Rock cress (Arabis spp.) | 18 – 21 | 65 – 70 | No |
Rudbeckia (Rudbeckia spp.) | 21 – 23 | 70 – 73 | No |
Salvia (Salvia officinalis) | 21 – 23 | 70 – 73 | No |
Satin flower (Clarkia amoena) | 21 – 23 | 70 – 73 | No |
Shooting star (Dodecatheon meadia) | 18 – 21 | 65 – 70 | Yes |
Sea holly (Eryngium spp.) | 18 – 23 | 65 – 73 | Yes |
Shasta daisy (Leucanthemum x superbum) | 18 – 21 | 65 – 70 | No |
Snapdragon (Antirrhinum majus) | 18 – 23 | 65 – 73 | Yes |
Snow-in-summer (Cerastium tomentosum) | 18 – 21 | 65 – 70 | No |
Speedwell (Veronica spp.) | 18 – 24 | 65 – 75 | No |
Spider flower (Cleome spinosa) | 21 – 23 | 70 – 73 | Yes |
Statice (Limonium sinuatum) | 15 – 20 | 60 – 68 | No |
Stock (Matthiola incana) | 15 – 18 | 60 – 65 | No |
Stoke’s aster (Stokesia laevis) | 21 – 24 | 70 – 75 | No |
Sunflower (Helianthus spp.) | 21 – 23 | 70 – 73 | No |
Swan river daisy (Brachyscome iberidifolia) | 21 – 24 | 70 – 78 | No |
Sweet pea (Lathyrus odoratus) | 12 – 18 | 55 – 65 | No |
Trumpet flower (Incarvillea spp.) | 18 – 21 | 65 – 70 | No |
Tweedia (Oxypetalum coeruleum) | 18 – 21 | 65 – 70 | No |
Twinspur (Diascia spp.) | 15 – 18 | 60 – 65 | No |
Verbena (Verbena spp.) | 18 – 23 | 65 – 73 | No |
Viola (Viola spp.) | 18 – 23 | 65 – 73 | No |
Virginian stock (Malcolmia maritima) | 18 – 23 | 65 – 73 | No |
Wallflower (Erysimum cheiri, syn. Cheiranthus cheiri) | 15 – 18 | 60 – 65 | No |
Wild indigo (Baptisia spp.) | 18 – 21 | 65 – 70 | No |
Wishbone flower (Torenia fournieri) | 21 – 23 | 70 – 75 | No |
Xeranthemum (Xeranthemum annuum) | 24-35 | 75 – 95 | No |
Yarrow (Achillea spp.) | 18 – 21 | 65 – 70 | Yes |
Yellow lotus (Nelumbo lutea) | 21 – 24 | 70 – 78 | No |
Zinnia (Zinnia spp.) | 21 – 23 | 70 – 73 | No |