Annuals Gardening Sowing Seeds

Sowing Calendar for Annual Flowers

Confused boy looks at seed capsules but doesn't know when to sow seeds.

Ill.: zynga2-a.akamaihd.net, clipartandscrap.com & assets.podomatic.net

The following list presents about 150 annuals with the recommended sowing date for each one. If you see the mention “8 weeks,” that means you should sow it indoors 8 weeks before the date when you expect to be transplanting it to the garden. Note that this date is not necessarily 8 weeks before the last frost date, as the soil and air may still be very cold at that time, but probably about 7 to 14 days later.

This image has an empty alt attribute; its file name is 20210303b-eng-calcul-frost-date.jpg

For example, where I live, the official last frost date is June 1st, but that refers to the average date of last frost. About 50% of the time, there is frost after that date. That’s why I usually use June 10 as a safe planting-out date for the seedlings I started indoors and it’s the one I use in calculating when to start my seedlings.

Sowing Dates for Annuals

VarietyWeeks Indoors
Agastache (Agastache rupestrisA. cana and others)8 weeks
Ageratum (Ageratum houstonianum) 4 weeks or sow outdoors
Alternanthera (Alternanthera dentata and others)11 weeks
Alyssum, Sweet (Lobularia maritima)4 weeks or sow outdoors
Amaranth (Amaranthus caudatus)4 weeks or sow outdoors
Amaranth, Globe (Gomphrena globosa and others)6 weeks or sow outdoors
Angelonia (Angelonia angustifolia)8 weeks
Aster, China (Callistephus chinensis) 6 weeks or sow outdoors6 weeks or sow outdoors
Baby Blue Eyes (Nemophila spp.)4 weeks or sow outdoors
Baby’s Breath, Annual (Gypsophila elegans) 4 weeks or sow outdoors
Baby’s Breath, Cushion (Gypsophila muralis)6 weeks or sow outdoors
Bachelor’s Button, Annual (Centaurea cyanus and others) 4 weeks or sow outdoors
Bacopa (Sutera cordata)10 weeks
Balsam, Garden (Impatiens balsamina)4 weeks or sow outdoors
Bean, Castor (Ricinus communis) 4 weeks or sow outdoors
Bean, Hyacinth (Lablab purpureus, syn. Dolichos lablab)6 weeks or sow outdoors
Bean, Scarlet Runner (Phaseolus coccineus)2 weeks or sow outdoors
Begonia, Tuberous (Begonia × tuberhybrida) 16 weeks
Begonia, Wax (Begonia × semperflorens-cultorumB. × benariensis and other non-tuberous varieties) 12 weeks
Bells of Ireland (Moluccella laevis)10 weeks or sow outdoors early
Black-Eyed Susan (Rudbeckia hirta)6 weeks or sow outdoors
Black-Eyed Susan Vine (Thunbergia alata)6 weeks or sow outdoors
Bloodleaf (Iresine spp.)10 weeks
Blue Stars (Isotoma axillaris, syn. Laurentia axillaris) 14 weeks
Browallia (Browallia spp.)8 weeks
Bunny Tail (Lagurus ovatus) 6 weeks or sow outdoors
Burning Bush (Bassia scoparia, syn. Kochia scoparia) 6 weeks or sow outdoors
Cabbage, Ornamental (Brassica olearcea acephala) 4 weeks or sow outdoors
Calibrachoa (Calibrachoa × hybrida) 8 weeks
Calliopsis (Coreopsis tinctoria and others)6 weeks or sow outdoors
Canna (Canna spp.)8 weeks
Carnation (Dianthus caryophyllus) 10 weeks
Castor Oil Plant (Ricinus communis) 4 weeks or sow outdoors
Cathedral Bells (Cobaea scandens) 10 weeks
Celosia (Celosia argentea and others)4 weeks or sow outdoors
Chrysanthemum, Annual (Glebionis carinatum, syn. Chrysanthemum carinatum) 6 weeks or sow outdoors
Chrysanthemum, Crown (Glebionis coronaria syn. Chrysanthemum coronarium)6 weeks or sow outdoors
Clarkia (Clarkia unguiculata, syn. C. elegans) 6 weeks or sow outdoors
Cleome (Cleome hasslerana and others)4 weeks or sow outdoors
Coleus (Coleus scutellarioides)8 weeks
Coreopsis, Plains (Coreopsis tinctoria and others) 6 weeks or sow outdoors
Corn-cockle (Agrostemma githago and others) 6 weeks or sow outdoors
Cosmidium (Thelesperma burridgeanum, syn. Cosmidium burridgeanum)6 weeks or sow outdoors
Cosmos (Cosmos bipinnatus and C. sulphureus)4 weeks or sow outdoors
Cup-and-saucer Vine (Cobaea scandens) 10 weeks
Cupflower (Nierembergia hippomanica and others) 10 weeks or sow outdoors
Dahlia, Dwarf (Dahlia × hortensis)6 weeks or sow outdoors
Dahlia, Tall and Medium (Dahlia × hortensis)8 weeks or sow outdoors
Daisy, African (Arctotis × hybrida, formerly Venidium)6 weeks or sow outdoors
Daisy, African (Osteospermum ecklonis, syn. Dimorphotheca ecklonis)6 weeks or sow outdoors
Daisy, Dahlberg (Thymophylla tenuiloba, syn. Dyssodia tenuiloba) 6 weeks or sow outdoors
Daisy, Livingston (Dorotheanthus bellidiformis and Mesembryanthemum crystallinum)10 weeks
Datura or Devil’s Trumpet (Datura metel and D. innoxia)16 weeks or sow outdoors
Dichondra (Dichondra repens) 8 weeks
Dracaena, Spike (Cordyline australis, syn. C. indivisa) 22 weeks
Dusty Miller (Senecio cineraria and others, Centaurea cineraria)12 weeks
Eucalyptus (Eucalyptus cinereaE. globulus and others) 10 weeks
Everlasting, Annual (Xeranthemum annuum) 6 weeks or sow outdoors
Everlasting, Golden (Xerochrysum bracteatum, syn. Helichrysum bracteatum) 6 weeks or sow outdoors
Everlasting, Winged (Ammobium alataum) 6 weeks or sow outdoors
Felicia (Felicia bergeriana and F. heterophylla) 4 weeks or sow outdoors
Flax (Linum grandiflorumL. usitatissimum and others) 3 weeks or sow outdoors
Flossflower (Ageratum houstonianum) 4 weeks or sow outdoors
Forget-Me-Not, Chinese (Cynoglossum amabile)6 weeks or sow outdoors
Four O’Clock (Mirabilis jalapa) 6 weeks or sow outdoors
Fuchsia (Fuchsia × hybrida) 14 weeks
Gaillardia, Annual (Gaillardia pulchella)4 weeks or sow outdoors
Gazania (Gazania rigens) 6 weeks or sow outdoors
Geranium, Ivy (Pelargonium peltatum) 12 weeks
Geranium, Zonal (Pelargonium × hortorum) 12 weeks
Godetia (Clarkia amoena, formerly Godetia amoena)6 weeks or sow outdoors
Gourd, Ornamental (Cucurbita pepo and Lagenaria siceraria) 3 weeks or sow outdoors
Grass, Fountain (Pennisetum villosumP. setaceum) 6 week or sow outdoors
Grass, Hare’s Tail (Lagurus ovatus) 6 weeks or sow outdoors
Heliotrope (Heliotropium arborescens) 10 weeks
Hibiscus, Red-Leaf (Hibiscus acetosella) 10 weeks
Honeywort (Cerinthe major) 10 weeks or sow outdoors
Impatiens, African (Impatiens auricoma and its hybrids) 8 weeks
Impatiens, Common (Impatiens walleriana) 10 weeks
Impatiens, New Guinea (Impatiens × hawkeri) 10 weeks
Jewels of Opar (Talinum paniculatum and others)6 weeks or sow outdoors
Jewelweed, Ornamental (Impatiens glandulifera) 4 weeks or sow outdoors
Joseph’s Coat (Amaranthus tricolor) 4 weeks or sow outdoors
Kale, Ornamental (Brassica olearcea acephala) 4 weeks or sow outdoors
Kiss-Me-Over-the-Garden-Gate (Persicaria orientalis, syn. Polygonum orientale) 4 weeks or sow outdoors
Knotweed, Pink (Persicaria capitata, syn. Polygonum capitatum) 10 weeks or sow outdoors
Larkspur (Consolida ambigua and C. regalis, formerly Delphinium) 6 weeks or sow outdoors early
Laurentia (Isotoma axillaris, syn. Laurentia axillaris) 14 weeks
Lisianthus (Eustoma grandiflora) 18 weeks
Lobelia, Bedding (Lobelia erinus) 8 weeks or sow outdoors
Love-in-a-Mist (Nigella damascena and others) 6 weeks or sow outdoors
Love-lies-bleeding (Amaranthus caudatus)4 weeks or sow outdoors
Mallow, Rose (Malva trimestris, syn. Lavatera trimestris)6 weeks or sow outdoors
Maple, Flowering (Abutilon spp.)12 weeks
Marigold, African (Tagetes erecta) 4 weeks or sow outdoors
Marigold, French (Tagetes patula and T. patula × erecta)4 weeks or sow outdoors
Marigold, Pot (Calendula officinalis) 6 weeks or sow outdoors
Melampodium (Melampodium paludosum)6 weeks or sow outdoors
Mignonette (Reseda odorata) 6 weeks or sow outdoors
Milkweed, Tropical (Asclepias curassavica) 10 weeks
Millet, Ornamental (Pennisetum glaucum) 8 weeks
Million Bells (Calibrachoa × hybrida)8 weeks
Mimulus (Mimulus × hybridus) 8 weeks or sow outdoors
Morning Glory, Climbing (Ipomoea tricolor, I. nil, etc.) 3 weeks or sow outdoors
Morning Glory, Dwarf (Convolvulus tricolor)5 weeks or sow outdoors
Nasturtium (Tropaeolum majus and others)2 weeks or sow outdoors
Nemesia (Nemesia strumosa and others)6 weeks or sow outdoors
Nicandra (Nicandra physaloides) 6 weeks or sow outdoors
Nierembergia (Nierembergia hippomanica and others)10 weeks
Nolana (Nolana paradoxa and N. humifusa) 4 weeks or sow outdoors
Painted Tongue (Salpiglossis sinuata) 8 weeks or sow outdoors
Palm, Cabbage (Cordyline australis, syn. C. indivisa) 22 weeks
Pansy (Viola × wittrockiana)8 weeks or sow outdoors
Pelargonium, Ivy (Pelargonium peltatum) 12 weeks
Pelargonium, Zonal (Pelargonium × hortorum)12 weeks
Penstemon, Annual (Penstemon hartwegiiP. × gloxinioides, etc.)12 weeks
Periwinkle, Madagascar (Catharanthus roseus)12 weeks
Petunia (Petunia × atkinsiana and others)10 weeks
Phacelia (Phacelia campanulariaP. tanacetifolia and others)4 weeks or sow outdoors
Phlox, Annual (Phlox drummondii) 6 weeks or sow outdoors
Pincushion Flower, Annual (Scabiosa atropurpurea) 6 weeks or sow outdoors
Pink, China (Dianthus chinensis) 8 weeks or sow outdoors
Policeman’s Helmet (Impatiens glandulifera)4 weeks or sow outdoors
Polka Dot Plant (Hypoestes phyllostachys) 10 weeks
Poppy, California (Eschscholzia californica) 2 weeks or sow outdoors
Poppy, Mexican (Argemone mexicana and others)6 weeks or sow outdoors
Poppy, Opium (Papaver somniferum, syn. P. laciniatumP. paeoniflorum)6 weeks or sow outdoors
Poppy, Shirley (Papaver rhoeas and P. commutatum) Sow outdoors
Poppy, Tulip (Hunnemannia fumariifolia) 6 weeks or sow outdoors
Portulaca (Portulaca grandiflora)6 weeks or sow outdoors
Sage, Mealy (Salvia farinacea) 12 weeks
Sage, Painted (Salvia viridis, syn. S. horminus) 6 weeks or sow outdoors
Sage, Scarlet (Salvia splendens) 6 weeks
Sensitive Plant (Mimosa pudica) 10 weeks
Shoo-Fly Plant (Nicandra physaloides) 6 weeks or sow outdoors
Snapdragon (Antirrhinum majus)6 weeks or sow outdoors
Snapdragon, Climbing (AsarinaLophospermum and Maurandya) 11 weeks
Snapdragon, Fairy (Chaenorrhinum origanifolium, syn. C. glaerosum)16 weeks
Sneezeweed, Yellow (Helenium amarum) 8 weeks or sow outdoors
Snow on the Mountain (Euphorbia marginata) 6 weeks or sow outdoors
Spiderflower (Cleome hasslerana and others) 4 weeks or sow outdoors
Star Flower (Isotoma axillaris, syn. Laurentia axillaris) 14 weeks
Statice, Annual (Limonium sinuatum and others) 4 weeks or sow outdoors
Stock, Brompton (Matthiola incana)6 weeks or sow outdoors
Stock, Virginia (Malcomia maritima) 4 weeks or sow outdoors
Strawflower (Xerochrysum bracteatum, syn. Helichrysum bracteatum) 6 weeks or sow outdoors
Sunflower (Helianthus annuus and others) 4 weeks or sow outdoors
Sunflower, Mexican (Tithonia rotundifolia) 6 weeks or sow outdoors
Sunray, Pink (Rhodanthe chlorocephala rosea and R. manglesii, syn. Acroclinium and Helipterum) 6 weeks or sow outdoors
Sweet Pea (Lathyrus odoratus) 4 weeks or sow outdoors
Sweet William (Dianthus barbatus) 8 weeks
Thorn apple or jimsonweed (Datura stramomium and others)  6 weeks or sow outdoors 
Throatwort, Blue (Trachelium caeruleum) 10 weeks
Tickseed (Bidens aureaB. ferulifolia and others) 6 weeks
Tickseed, Garden (Coreopsis tinctoria and others)6 weeks or sow outdoors
Toadflax (Linaria reticulataL. maroccana, etc.)8 weeks or sow outdoors
Tobacco, Flowering (Nicotiana alataN. sylvestris and others) 6 weeks or sow outdoors
Toothache Plant (Acmella oleracea, syn. Spilanthes acmella) 11 weeks
Verbena, Hybrid (Verbena × hybrida) 10 weeks
Verbena, Tall (Verbena bonariensis) 8 weeks or sow outdoors
Wishbone Flower (Torenia fournieri and others) 8 weeks
Zinnia (Zinnia elegansZ. haageanaZ. angustifolia, etc.)4 weeks or sow outdoors
Zinnia, African (Melampodium paludosum) 6 weeks or sow outdoors
Zinnia, Creeping (Sanivitalia procumbens)6 weeks or sow outdoors

If you follow the dates suggested in the list above, that should give you annuals of just the right size for transplanting to the garden.

Best of luck with all your seedlings!

Article partly based on one that appeared in this blog on January 17, 2018

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

4 comments on “Sowing Calendar for Annual Flowers

  1. Veronica

    Thank you, Larry! I wish I spoke French so I could read more of your books!

    Do you have any advice for sowing annual poppies? (Somniferum?) I read conflicting things on various websites — do they need stratification? can I throw them on snow? do they hate transplanting?

    • What obviously happens is that different people try different processes… and some of them work. The same seed could have more than one set conditions for germination. So various bits of information float around. It would really be practical to have a central source for verified seed sprouting information, but I don’t know of one.

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