Many seeds require pre-treatment before they are sowed. The three most common treatments are scarification, stratification and soaking. These treatments mimic the type of exposure seeds would experience in the wild.
Seeds undergo a period of dormancy which protects the seed from germinating at the wrong time which could kill it. Once the right conditions are met, the seed germinates. Tough outer coats can protect the seed from the elements. In the wild, extended exposure to moisture will eventually wear the coat down, allowing water to penetrate.
In the wild, seeds will experience a winter period, and germination is triggered once the weather warms up. As our seeds are kept in a constant temperature, they do not experience a period of cold. Stratification involves storing seeds in a refrigerator for weeks or months to simulate winter. They may be kept in moist paper towels or dry.
Scarification
Some seeds have a tough outer coat that needs to be worn down to let moisture in and trigger germination. There are several ways to scarify seeds, the most common method is to use sandpaper or a nail file to gently rough up the outer coat.
Stratification
Stratification is a period of enforced cold that mimic winter and may be moist or dry. The period of stratification differs between species and can range from two weeks to two months.
Soaking
Soaking is another method to soften a seed’s coat and allows it to germinate faster. There are several methods to soak including water, and chemicals.
Are these treatments necessary?
Not always, but following these treatments will increase your germination rate, resulting in more viable plants. I have sowed a number of seeds that require cold stratification without doing so, and still had success. But,
Scarification |
Stratification |
Soaking | |
| African daisy (Arctotis stoechadifolia) | No | No | No |
| African daisy (Osteospermum spp.) | Yes | No | No |
| Alfalfa (Medicago sativa) | Yes | No | Yes |
| Alyssum (Lobularia maritima) | No | No | No |
| Amaranth (Amaranthus spp.) | Yes | No | No |
| Amethist flower (Browallia spp.) | No | No | No |
| Anise hyssop (Agastache foeniculum) | No | Yes | No |
| Armenian cucumber (Cucumis melo var. flexuosus) | No | No | No |
| Arnica (Arnica montana) | No | Yes | No |
| Artichoke (Cynara cardunculus var. scolymus) | No | Yes | Yes |
| Aspagagus (Asparagus officinalis) | No | Yes | Yes |
| Aster (Aster spp.) | No | No | No |
| Baby’s breath (Gypsophila spp.) | No | No | No |
| Balloon flower (Platycodon grandiflorus) | No | No | No |
| Basil (Ocimum basilicum) | No | No | Yes |
| Bear’s breeches (Acanthus mollis) | No | No | Yes |
| Bee balm (Monarda didyma) | No | No | No |
| Beetroot (Beta vulgaris) | No | No | Yes |
| Begonia (Begonia spp.) | No | No | No |
| Bellflower (Campanula spp.) | No | Yes | No |
| Bells-of-Ireland (Moluccella laevis) | No | Yes | No |
| Berberis (Berberis spp.) | No | Yes | No |
| Bergamot (Monarda didyma) | No | No | No |
| Betony (Stachys officinalis) | No | Yes | No |
| Bilberry (Vaccinium myrtillus) | No | Yes | No |
| Black-eyed Susan (Rudbeckia hirta) | No | Yes | No |
| Bleeding heart (Dicentra spectabilis) | No | Yes | No |
| Blanket flower (Gaillardia x grandiflora) | No | No | No |
| Bloodroot (Sanguinaria canadensis) | No | Yes | Yes |
| Blue felecia bush (Felicia amelloides) | No | Yes | No |
| Blue vervain (Vebena hastata) | No | Yes | No |
| Bok choy (Brassica rapa subsp. chinensis) | No | No | No |
| Boltonia (Boltonia spp.) | No | No | No |
| Boneset (Eupatorium perfoliatum) | No | Yes | No |
| Borage (Borago officinalis) | No | Yes | No |
| Broad bean (Vicia faba) | Yes | Yes | No |
| Broccoli (Brassica oleracea var. italica) | No | No | No |
| Brussels sprouts (Brassica oleracea var. gemmifera) | No | No | No |
| Bugloss (Anchusa capensis) | No | Yes | No |
| Burnet (Sanguisorba minor) | No | Yes | No |
| Butter daisy (Melampodium paludosum) |
No | No | No |
| Butterfly bush (Buddleja spp.) | No | Yes | No |
| Butterfly flower (Schizanthus spp.) | No | No | No |
| Butterfly pea (Clitoria ternatea) | Yes | No | Yes |
| Butterfly weed (Asclepias tuberosa) | No | Yes | Yes |
| Cabbage (Brassica oleracea var. capitata) | No | No | No |
| Calendula (Calendula officinalis) | No | No | No |
| Californian poppy (Eschscholzia californica) | No | No | No |
| Camas (Camassia spp.) | No | Yes | No |
| Candytuft (Iberis spp.) | No | No | No |
| Canterbury bells (Campanula medium) | No | Yes | No |
| Cape jewels (Nemesia strumosa) | No | No | No |
| Capsicum (Capsicum annuum) | No | No | No |
| Carnation (Dianthus spp.) | No | No | No |
| Carob (Ceratonia siliqua) | Yes | No | No |
| Carrot (Daucus carota) | No | No | Yes |
| Catnip/catmint (Nepeta spp.) | No | Yes |
Yes |
| Cauliflower (Brassica oleracea var. botrytis) | No | No | No |
| Celeriac (Apium graveolens var. rapaceum) | No | No | No |
| Celery (Apium graveolens) | No | No | No |
| Chamomile (Matricaria chamomilla) | No | Yes | No |
| Chicory radicchio (Cichorium intybus var. foliosum) | No | No | No |
| Chilean bellflower (Lapageria rosea) | No | Yes | No |
| Chilli (Capsicum spp.) | No | No | No |
| Chives (Allium schoenoprasum) | No | No | No |
| Chinese aster (Callistephus chinensis) | No | No | No |
| Chinese blackberry lily (Belamcanda chinensis) |
No | Yes | No |
| Chinese cabbage (Brassica rapa subsp. pekinensis) | No | No | No |
| Chinese forget-me-not (Cynoglossum amabile) |
No | Yes | No |
| Chinese lantern (Physalis alkekengi) | No | Yes | No |
| Chrysanthemum (Chrysanthemum spp.) | No | No | No |
| Clematis (Clematis spp.) | No | Yes | No |
| Climbing bean (Phaseolus coccineus) | No | No | Yes |
| Cliquefoil (Potentilla spp.) | No | No | No |
| Cohosh (Cimicifuga spp.) | No | Yes | Yes |
| Columbine (Aquilegia spp.) | No | No | No |
| Common rockrose (Helianthemum nummularium) | No | No | No |
| Common sneezeweed (Helenium autumnale) | No | No | Yes |
| Comfrey (Symphytum spp.) | No | Yes | No |
| Coral bell (Heuchera spp.) | No | Yes | No |
| Coriander (Coriandrum sativum) | No | No | No |
| Corncockle (Agrostemma githago) | No | No | No |
| Cornflower (Centaurea cyanus) | No | No | No |
| Coriander (Coriandrum sativum) |
No | Yes | Yes |
| Cosmos (Cosmos bipinnatus) | No | No | No |
| Cress (Lepidium sativum) | No | No | No |
| Cucamelon (Melothria scabra) | No | No | No |
| Cucumber (Cucumis sativus) | No | No | No |
| Cup and saucer vine (Cobaea scandens) | No | No | Yes |
| Cupflower (Nierembergia spp.) | No | No | No |
| Cupid’s bow (Achimenes spp.) | Yes | No | No |
| Cupid’s dart (Catananche caerulea) | No | No | No |
| Cyclamen (Cyclamen spp.) | No | No | Yes |
| Dahlberg daisy (Thymophylla tenuiloba) | No | No | No |
| Dahlia (Dahlia spp.) | No | No | No |
| Delphinium (Delphinium elatum) | No | Yes | No |
| Dill (Anethum graveolens) | No | Yes | No |
| Eastern redbud (Cercis canadensis) |
Yes | Yes | Yes |
| Echinacea (Echinacea spp.) | No | Yes | Yes |
| Edeiweiss (Leontopodium alpinum) |
No | No | No |
| Eggplant (Solanum melongena) | No | No | No |
| Elderberry (Galium aparine) | No | Yes | No |
| English daisy (Bellis perennis) | No | No | No |
| Endive (Cichorium endivia) | No | No | No |
| Evening primrose (Oenothera spp.) | No | No | Yes |
| Everlasting (Helichrysum bracteatum) | No | No | No |
| False goat’s beard (Astilbe spp.) | Yes | No | No |
| False indigo (Amorpha spp.) | Yes | Yes | Yes |
| False sunflower (Heliopsis spp.) | No | Yes | No |
| Fan flower (Scaevola aemula) | No | No | No |
| Fennel (Foeniculum vulgare) | No | Yes | Yes |
| Fenugreek (Trigonella foenum-graecum) | Yes | No | No |
| Feverfew (Tanacetum parthenium) | No | No | No |
| Firecracker flower (Crossandra infundibuliformis) | No | No | Yes |
| Flax (Linum usitatissimum) | No | No | No |
| Fleabane (Erigeron spp.) | No | No | No |
| Floss flower (Ageratum houstonianum) | No | Yes | No |
| Forget-me-non toxict (Myosotis spp.) | No | No | No |
| Foxglove (Digitalis spp.) | No | Yes | No |
| Foxtail lily (Eremurus robustus) | Yes | Yes | Yes |
| Fuscia (Fuchsia spp.) | No | Yes | Yes |
| Garden heliotrope (Heliotropium spp.) | Yes | Yes | No |
| Gay feather (Liatris spp.) | No | Yes | No |
| Gazania (Gazania spp.) | No | No | No |
| Gentium (Gentiana spp.) | No | Yes | No |
| Geranium (Pelargonium spp.) | Yes | No | No |
| Gerbera (Gerbera spp.) | No | No | No |
| Geum (Geum spp.) | Yes | Yes | No |
| Ginseng (Panax spp.) | No | Yes | No |
| Globe amaranth (Gomphrena globosa) | No | No | No |
| Globeflower (Trollius spp.) | No | Yes | No |
| Gloxinia (Sinningia speciosa) | No | No | No |
| Goldencup (Hunnemannia fumariifolia) | No | No | Yes |
| Goldenrod (Solidago spp.) | No | Yes | No |
| Goldenseal (Hydrastis canadensis) | No | Yes | Yes |
| Goldentuft (Aurinia saxatilis) | No | No | No |
| Heather (Calluna vulgaris) | No | No | No |
| Hellebore (Helleborus spp.) | No | Yes | No |
| Hemp agrimony (Eupatorium cannabinum) | No | Yes | No |
| Hibiscus (Hibiscus spp.) | No | Yes | No |
| Hollyhock (Alcea rosea) | No | Yes | No |
| Hydrangea (Hydrangea spp.) | No | No | No |
| Iceland poppy (Papaver nudicaule) | No | No | No |
| Impatiens (Impatiens spp.) | No | No | No |
| Jacob’s ladder (Polemonium spp.) | No | No | No |
| Juniper (Juniperus spp.) | Yes | Yes | Yes |
| Kale (Brassica oleracea var. sabellica) | No | No | No |
| Kohlrabi (Brassica oleracea var. gongylodes) | No | No | No |
| Laceflower (Trachymene coerulea) | No | No | No |
| Lady’s mantle (Alchemilla spp.) | No | No | No |
| Ladys purse (Calceolaria spp.) | No | No | No |
| Larkspur (Consolida ambigua) | No | Yes | No |
| Lavender (Lavandula spp.) | No | Yes | No |
| Leek (Allium ampeloprasum var. porrum) | No | No | No |
| Lemon balm (Melissa officinalis) | Yes | Yes | No |
| Lemongrass (Cymbopogon citratus) | No | No | No |
| Leopard plant (Ligularia spp.) | No | No | Yes |
| Leopard’s bane (Doronicum cordatum) | No | No | No |
| Lettuce (Lactuca sativa) | No | No | No |
| Licorice (Glycyrrhiza glabra, G. uralensis) | Yes | Yes | No |
| Lilac (Syringa spp.) | No | Yes | Yes |
| Linaria (Linaria spp.) | No | No | No |
| Lisianthus (Eustoma grandiflorum) | No | No | No |
| Livingstone daisy (Dorotheanthus bellidiformis) | No | No | Yes |
| Lobelia (Lobelia spp.) | No | No | No |
| Lomatium (Lomatium dissectum) | Yes | Yes | No |
| Love-lies-bleeding (Amaranthus caudatus) | Yes | Yes | Yes |
| Lupine (Lupinus spp.) | Yes | Yes | Yes |
| Madagascar periwinkle (Catharanthus roseus) | No | No | No |
| Maltese cross (Lychnis chalcedonica) | No | Yes | No |
| Marigold (Tagetes spp.) | No | No | No |
| Marshmallow plant (Althaea officinalis) | No | Yes | No |
| Masterwort (Astrantia spp.) | No | Yes | No |
| Meadowsweet (Filipendula ulmaria) | No | Yes | No |
| Mexican creeping zinnia (Sanvitalia procumbens) |
No | No | No |
| Mexican sunflower (Tithonia spp.) | No | No | No |
| Mignon toxicnette (Reseda odorata) | No | No | No |
| Milkvetch (Astragalus spp.) | Yes | Yes | No |
| Milkweed (Asclepias spp.) | No | Yes | No |
| Mizuna (Brassica rapa var. Laciniifolia) | No | No | No |
| Monkey flowers (Mimulus spp.) | No | Yes | No |
| Monk’s hood (Aconitum spp.) | No | Yes | No |
| Morning glory (Convolvulus spp.) |
Yes | No | No |
| Motherwort (Leonurus cardiaca) | No | Yes | No |
| Mountain mint (Pycnanthemum virginianum) | No | Yes | No |
| Mugwort (Artemisia vulgaris) | No | Yes | No |
| Mullein (Verbascum) | No | Yes | No |
| Musk mallow (Malva moschata) | No | No | No |
| Mustard (Brassica nigra) | No | No | No |
| Nasturtium (Tropaeolum majus) | Yes | No | Yes |
| Nemesia (Nemesia spp.) | No | No | No |
| Nemophila (Nemophila spp.) | No | No | No |
| Nigella (Nigella damascena) | No | No | Yes |
| Obedient plant (Physostegia virginiana) | No | Yes | No |
| Okra (Abelmoschus esculentus) | Yes | No | Yes |
| Oregano (Origanum vulgare) |
No | Yes | No |
| Pansy (Viola tricolor var. hortensis) | No | Yes | No |
| Curly parsley (Petroselinum crispum) | No | No | No |
| Continental parsley (Petroselinum crispum neapolitanum) |
No | No | No |
| Pea (Pisum sativum) | Yes | No | Yes |
| Pearly everlasting (Anaphalis margaritacea) | No | Yes | No |
| Pentstemon (Penstemon hartwegii) | No | Yes | No |
| Peony (Paeonia spp.) | Yes | Yes | Yes |
| Persian violet (Exacum affine) | No | No | No |
| Peruvian lily (Alstroemeria spp.) | No | Yes | Yes |
| Petunia (Petunia spp.) | No | No | No |
| Phlox (Phlox spp.) | No | Yes | No |
| Pincushion flower (Scabiosa spp.) | No | Yes | No |
| Plantago (Plantago rugelii) | No | Yes | No |
| Poppy (Papaver spp.) | No | Yes | Yes |
| Portulaca (Portulaca spp.) | No | No | No |
| Potato bean (Apios americana) | Yes | Yes | Yes |
| Pride of Madeira (Echium candicans) | No | No | No |
| Primrose (Primula spp.) | No | Yes | No |
| Purple rock cress (Aubrieta deltoidea) | No | No | No |
| Pumpkin (Cucurbita spp.) | No | No | Yes |
| Queen Anne’s lace (Daucus carota) | No | No | No |
| Radish (Raphanus sativus) | No | No | No |
| Rhubarb (Rheum rhabarbarum) | No | No | Yes |
| Rock cress (Arabis spp.) | No | No | No |
| Rocket (Eruca vesicaria ssp. sativa) | No | No | No |
| Rockmelon (Cucumis melo var. cantalupensis) | No | No | Yes |
| Rosemary (Salvia rosmarinus) | No | Yes | No |
| Sage (Salvia officinalis) | No | Yes | No |
| Saint John’s wort (Hypericum perforatum) | No | Yes | Yes |
| Salvia (Salvia officinalis) | No | No | No |
| Satin flower (Clarkia amoena) | No | No | No |
| Savory (Satureja hortensis) | No | No | No |
| Shooting star (Dodecatheon meadia) | No | No | No |
| Sea holly (Eryngium spp.) | No | Yes | No |
| Sea kale (Crambe maritime) | No | Yes | No |
| Shasta daisy (Leucanthemum x superbum) | No | No | No |
| Silver beet (Beta vulgaris var. cicla) | No | No | Yes |
| Snapdragon (Antirrhinum majus) | No | No | No |
| Snow-in-summer (Cerastium tomentosum) | No | No | No |
| Society garlic (Tulbaghia violacea) |
No | No | No |
| Speedwell (Veronica spp.) | No | Yes | No |
| Spider flower (Cleome hassleriana) | No | Yes | Yes |
| Spinach (Spinacia oleracea) | No | No | No |
| Spring onion (Allium fistulosum) | No | No | No |
| Squash (Cucurbita spp.) | No | No | Yes |
| Statice (Limonium sinuatum) | No | No | No |
| Stinging nettle (Urtica dioica) | No | Yes | No |
| Stock (Matthiola incana) | No | No | No |
| Stoke’s aster (Stokesia laevis) | No | No | No |
| Sunflower (Helianthus spp.) | Yes | Yes | Yes |
| Swan river daisy (Brachyscome iberidifolia) | No | No | No |
| Swede (Brassica napus) | No | No | No |
| Sweet cicily (Myrrhis odorata) | No | Yes | No |
| Sweet pea (Lathyrus odoratus) | Yes | No | Yes |
| Sweet rocket (Hesperis matronalis) |
No | No | No |
| Tarragon (Artemisia dracunculus) | No | No | No |
| Thyme (Thymus vulgaris) | No | Yes | No |
| Tomato (Solanum lycopersicum) | Yes | No | Yes |
| Trumpet flower (Incarvillea spp.) | No | No | No |
| Turnip (Brassica rapa subsp. rapa) | No | No | No |
| Tweedia (Oxypetalum coeruleum) | No | No | No |
| Twinspur (Diascia spp.) | No | No | No |
| Valarian (Valeriana officinalis) | No | Yes | No |
| Verbena (Verbena spp.) | No | Yes | No |
| Viola (Viola spp.) | No | Yes | No |
| Virginian stock (Malcolmia maritima) | No | No | No |
| Wallflower (Erysimum cheiri, syn. Cheiranthus cheiri) | No | No | No |
| Watermelon (Citrullus lanatus) | Yes | No | Yes |
| Wild garlic (Allium ursinum) | No | Yes | No |
| Wild indigo (Baptisia spp.) | Yes | Yes | Yes |
| Wishbone flower (Torenia fournieri) | No | No | No |
| Xeranthemum (Xeranthemum annuum) |
No | No | No |
| Yarrow (Achillea spp.) | No | Yes | No |
| Zinnia (Zinnia spp.) | No | No | No |
| Zucchini (Cucurbita pepo) | Yes | No | Yes |
Julia is a writer and landscape consultant from Wollongong with a love of horticulture. She had been an avid gardener for over 30 years, collects rare variegated plants and is a home orchardist. Julia is passionate about learning and sharing her knowledge of plant propagation and plant toxicology. Whether it’s giving advice on landscape projects or sharing tips on growing, Julia enjoys helping people make their gardens flourish.
