Scarification, Stratification and Soaking Seeds

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)NoNoNo
African daisy (Osteospermum spp.)YesNoNo
Alfalfa (Medicago sativa)YesNoYes
Alyssum (Lobularia maritima)NoNoNo
Amaranth (Amaranthus spp.)YesNoNo
Amethist flower (Browallia spp.)NoNoNo
Anise hyssop (Agastache foeniculum)NoYesNo
Armenian cucumber (Cucumis melo var. flexuosus)NoNoNo
Arnica (Arnica montana)NoYesNo
Artichoke (Cynara cardunculus var. scolymus)NoYesYes
Aspagagus (Asparagus officinalis)NoYesYes
Aster (Aster spp.)NoNoNo
Baby’s breath (Gypsophila spp.)NoNoNo
Balloon flower (Platycodon grandiflorus)NoNoNo
Basil (Ocimum basilicum)NoNoYes
Bear’s breeches (Acanthus mollis)NoNoYes
Bee balm (Monarda didyma)NoNoNo
Beetroot (Beta vulgaris)NoNoYes
Begonia (Begonia spp.)NoNoNo
Bellflower (Campanula spp.)NoYesNo
Bells-of-Ireland (Moluccella laevis)NoYesNo
Berberis (Berberis spp.)NoYesNo
Bergamot (Monarda didyma)NoNoNo
Betony (Stachys officinalis)NoYesNo
Bilberry (Vaccinium myrtillus)NoYesNo
Black-eyed Susan (Rudbeckia hirta)NoYesNo
Bleeding heart (Dicentra spectabilis)NoYesNo
Blanket flower (Gaillardia x grandiflora)NoNoNo
Bloodroot (Sanguinaria canadensis)NoYesYes
Blue felecia bush (Felicia amelloides)NoYesNo
Blue vervain (Vebena hastata)NoYesNo
Bok choy (Brassica rapa subsp. chinensis)NoNoNo
Boltonia (Boltonia spp.)NoNoNo
Boneset (Eupatorium perfoliatum)NoYesNo
Borage (Borago officinalis)NoYesNo
Broad bean (Vicia faba)YesYesNo
Broccoli (Brassica oleracea var. italica)NoNoNo
Brussels sprouts (Brassica oleracea var. gemmifera)NoNoNo
Bugloss (Anchusa capensis)NoYesNo
Burnet (Sanguisorba minor)NoYesNo
Butter daisy (Melampodium
paludosum
)
NoNoNo
Butterfly bush (Buddleja spp.)NoYesNo
Butterfly flower (Schizanthus spp.)NoNoNo
Butterfly pea (Clitoria ternatea)YesNoYes
Butterfly weed (Asclepias tuberosa)NoYesYes
Cabbage (Brassica oleracea var. capitata)NoNoNo
Calendula (Calendula officinalis)NoNoNo
Californian poppy (Eschscholzia californica)NoNoNo
Camas (Camassia spp.)NoYesNo
Candytuft (Iberis spp.)NoNoNo
Canterbury bells (Campanula medium)NoYesNo
Cape jewels (Nemesia strumosa)NoNoNo
Capsicum (Capsicum annuum)NoNoNo
Carnation (Dianthus spp.)NoNoNo
Carob (Ceratonia siliqua)YesNoNo
Carrot (Daucus carota)NoNoYes
Catnip/catmint (Nepeta spp.)NoYes
Yes
Cauliflower (Brassica oleracea var. botrytis)NoNoNo
Celeriac (Apium graveolens var. rapaceum)NoNoNo
Celery (Apium graveolens)NoNoNo
Chamomile (Matricaria chamomilla)NoYesNo
Chicory radicchio (Cichorium intybus var. foliosum)NoNoNo
Chilean bellflower (Lapageria rosea)NoYesNo
Chilli (Capsicum spp.)NoNoNo
Chives (Allium schoenoprasum)NoNoNo
Chinese aster (Callistephus chinensis)NoNoNo
Chinese blackberry lily (Belamcanda
chinensis
)
NoYesNo
Chinese cabbage (Brassica rapa subsp. pekinensis)NoNoNo
Chinese forget-me-not (Cynoglossum
amabile
)
NoYesNo
Chinese lantern (Physalis alkekengi)NoYesNo
Chrysanthemum (Chrysanthemum spp.)NoNoNo
Clematis (Clematis spp.)NoYesNo
Climbing bean (Phaseolus coccineus)NoNoYes
Cliquefoil (Potentilla spp.)NoNoNo
Cohosh (Cimicifuga spp.)NoYesYes
Columbine (Aquilegia spp.)NoNoNo
Common rockrose (Helianthemum nummularium)NoNoNo
Common sneezeweed (Helenium autumnale)NoNoYes
Comfrey (Symphytum spp.)NoYesNo
Coral bell (Heuchera spp.)NoYesNo
Coriander (Coriandrum sativum)NoNoNo
Corncockle (Agrostemma githago)NoNoNo
Cornflower (Centaurea cyanus)NoNoNo
Coriander (Coriandrum
sativum
)
NoYesYes
Cosmos (Cosmos bipinnatus)NoNoNo
Cress (Lepidium sativum)NoNoNo
Cucamelon (Melothria scabra)NoNoNo
Cucumber (Cucumis sativus)NoNoNo
Cup and saucer vine (Cobaea scandens)NoNoYes
Cupflower (Nierembergia spp.)NoNoNo
Cupid’s bow (Achimenes spp.)YesNoNo
Cupid’s dart (Catananche caerulea)NoNoNo
Cyclamen (Cyclamen spp.)NoNoYes
Dahlberg daisy (Thymophylla tenuiloba)NoNoNo
Dahlia (Dahlia spp.)NoNoNo
Delphinium (Delphinium elatum)NoYesNo
Dill (Anethum graveolens)NoYesNo
Eastern redbud (Cercis
canadensis
)
YesYesYes
Echinacea (Echinacea spp.)NoYesYes
Edeiweiss (Leontopodium
alpinum
)
NoNoNo
Eggplant (Solanum melongena)NoNoNo
Elderberry (Galium aparine)NoYesNo
English daisy (Bellis perennis)NoNoNo
Endive (Cichorium endivia)NoNoNo
Evening primrose (Oenothera spp.)NoNoYes
Everlasting (Helichrysum bracteatum)NoNoNo
False goat’s beard (Astilbe spp.)YesNoNo
False indigo (Amorpha spp.)YesYesYes
False sunflower (Heliopsis spp.)NoYesNo
Fan flower (Scaevola aemula)NoNoNo
Fennel (Foeniculum vulgare)NoYesYes
Fenugreek (Trigonella foenum-graecum)YesNoNo
Feverfew (Tanacetum parthenium)NoNoNo
Firecracker flower (Crossandra infundibuliformis)NoNoYes
Flax (Linum usitatissimum)NoNoNo
Fleabane (Erigeron spp.)NoNoNo
Floss flower (Ageratum houstonianum)NoYesNo
Forget-me-non toxict (Myosotis spp.)NoNoNo
Foxglove (Digitalis spp.)NoYesNo
Foxtail lily (Eremurus robustus)YesYesYes
Fuscia (Fuchsia spp.)NoYesYes
Garden heliotrope (Heliotropium spp.)YesYesNo
Gay feather (Liatris spp.)NoYesNo
Gazania (Gazania spp.)NoNoNo
Gentium (Gentiana spp.)NoYesNo
Geranium (Pelargonium spp.)YesNoNo
Gerbera (Gerbera spp.)NoNoNo
Geum (Geum spp.)YesYesNo
Ginseng (Panax spp.)NoYesNo
Globe amaranth (Gomphrena globosa)NoNoNo
Globeflower (Trollius spp.)NoYesNo
Gloxinia (Sinningia speciosa)NoNoNo
Goldencup (Hunnemannia fumariifolia)NoNoYes
Goldenrod (Solidago spp.)NoYesNo
Goldenseal (Hydrastis canadensis)NoYesYes
Goldentuft (Aurinia saxatilis)NoNoNo
Heather (Calluna vulgaris)NoNoNo
Hellebore (Helleborus spp.)NoYesNo
Hemp agrimony (Eupatorium cannabinum)NoYesNo
Hibiscus (Hibiscus spp.)NoYesNo
Hollyhock (Alcea rosea)NoYesNo
Hydrangea (Hydrangea spp.)NoNoNo
Iceland poppy (Papaver nudicaule)NoNoNo
Impatiens (Impatiens spp.)NoNoNo
Jacob’s ladder (Polemonium spp.)NoNoNo
Juniper (Juniperus spp.)YesYesYes
Kale (Brassica oleracea var. sabellica)NoNoNo
Kohlrabi (Brassica oleracea var. gongylodes)NoNoNo
Laceflower (Trachymene coerulea)NoNoNo
Lady’s mantle (Alchemilla spp.)NoNoNo
Ladys purse (Calceolaria spp.)NoNoNo
Larkspur (Consolida ambigua)NoYesNo
Lavender (Lavandula spp.)NoYesNo
Leek (Allium ampeloprasum var. porrum)NoNoNo
Lemon balm (Melissa officinalis)YesYesNo
Lemongrass (Cymbopogon citratus)NoNoNo
Leopard plant (Ligularia spp.)NoNoYes
Leopard’s bane (Doronicum cordatum)NoNoNo
Lettuce (Lactuca sativa)NoNoNo
Licorice (Glycyrrhiza glabra, G. uralensis)YesYesNo
Lilac (Syringa spp.)NoYesYes
Linaria (Linaria spp.)NoNoNo
Lisianthus (Eustoma grandiflorum)NoNoNo
Livingstone daisy (Dorotheanthus bellidiformis)NoNoYes
Lobelia (Lobelia spp.)NoNoNo
Lomatium (Lomatium dissectum)YesYesNo
Love-lies-bleeding (Amaranthus caudatus)YesYesYes
Lupine (Lupinus spp.)YesYesYes
Madagascar periwinkle (Catharanthus roseus)NoNoNo
Maltese cross (Lychnis chalcedonica)NoYesNo
Marigold (Tagetes spp.)NoNoNo
Marshmallow plant (Althaea officinalis)NoYesNo
Masterwort (Astrantia spp.)NoYesNo
Meadowsweet (Filipendula ulmaria)NoYesNo
Mexican creeping zinnia (Sanvitalia
procumbens)
NoNoNo
Mexican sunflower (Tithonia spp.)NoNoNo
Mignon toxicnette (Reseda odorata)NoNoNo
Milkvetch (Astragalus spp.)YesYesNo
Milkweed (Asclepias spp.)NoYesNo
Mizuna (Brassica rapa var. Laciniifolia)NoNoNo
Monkey flowers (Mimulus spp.)NoYesNo
Monk’s hood (Aconitum spp.)NoYesNo
Morning glory (Convolvulus spp.)
YesNoNo
Motherwort (Leonurus cardiaca)NoYesNo
Mountain mint (Pycnanthemum virginianum)NoYesNo
Mugwort (Artemisia vulgaris)NoYesNo
Mullein (Verbascum)NoYesNo
Musk mallow (Malva moschata)NoNoNo
Mustard (Brassica nigra)NoNoNo
Nasturtium (Tropaeolum majus)YesNoYes
Nemesia (Nemesia spp.)NoNoNo
Nemophila (Nemophila spp.)NoNoNo
Nigella (Nigella damascena)NoNoYes
Obedient plant (Physostegia virginiana)NoYesNo
Okra (Abelmoschus esculentus)YesNoYes
Oregano (Origanum
vulgare
)
NoYesNo
Pansy (Viola tricolor var. hortensis)NoYesNo
Curly parsley (Petroselinum crispum)NoNoNo
Continental parsley (Petroselinum
crispum neapolitanum)
NoNoNo
Pea (Pisum sativum)YesNoYes
Pearly everlasting (Anaphalis margaritacea)NoYesNo
Pentstemon (Penstemon hartwegii)NoYesNo
Peony (Paeonia spp.)YesYesYes
Persian violet (Exacum affine)NoNoNo
Peruvian lily (Alstroemeria spp.)NoYesYes
Petunia (Petunia spp.)NoNoNo
Phlox (Phlox spp.)NoYesNo
Pincushion flower (Scabiosa spp.)NoYesNo
Plantago (Plantago rugelii)NoYesNo
Poppy (Papaver spp.)NoYesYes
Portulaca (Portulaca spp.)NoNoNo
Potato bean (Apios americana)YesYesYes
Pride of Madeira (Echium candicans)NoNoNo
Primrose (Primula spp.)NoYesNo
Purple rock cress (Aubrieta deltoidea)NoNoNo
Pumpkin (Cucurbita spp.)NoNoYes
Queen Anne’s lace (Daucus carota)NoNoNo
Radish (Raphanus sativus)NoNoNo
Rhubarb (Rheum rhabarbarum)NoNoYes
Rock cress (Arabis spp.)NoNoNo
Rocket (Eruca vesicaria ssp. sativa)NoNoNo
Rockmelon (Cucumis melo var. cantalupensis)NoNoYes
Rosemary (Salvia rosmarinus)NoYesNo
Sage (Salvia officinalis)NoYesNo
Saint John’s wort (Hypericum perforatum)NoYesYes
Salvia (Salvia officinalis)NoNoNo
Satin flower (Clarkia amoena)NoNoNo
Savory (Satureja hortensis)NoNoNo
Shooting star (Dodecatheon meadia)NoNoNo
Sea holly (Eryngium spp.)NoYesNo
Sea kale (Crambe maritime)NoYesNo
Shasta daisy (Leucanthemum x superbum)NoNoNo
Silver beet (Beta vulgaris var. cicla)NoNoYes
Snapdragon (Antirrhinum majus)NoNoNo
Snow-in-summer (Cerastium tomentosum)NoNoNo
Society garlic (Tulbaghia
violacea
)
NoNoNo
Speedwell (Veronica spp.)NoYesNo
Spider flower (Cleome hassleriana)NoYesYes
Spinach (Spinacia oleracea)NoNoNo
Spring onion (Allium fistulosum)NoNoNo
Squash (Cucurbita spp.)NoNoYes
Statice (Limonium sinuatum)NoNoNo
Stinging nettle (Urtica dioica)NoYesNo
Stock (Matthiola incana)NoNoNo
Stoke’s aster (Stokesia laevis)NoNoNo
Sunflower (Helianthus spp.)YesYesYes
Swan river daisy (Brachyscome iberidifolia)NoNoNo
Swede (Brassica napus)NoNoNo
Sweet cicily (Myrrhis odorata)NoYesNo
Sweet pea (Lathyrus odoratus)YesNoYes
Sweet rocket (Hesperis
matronalis
)
NoNoNo
Tarragon (Artemisia dracunculus)NoNoNo
Thyme (Thymus vulgaris)NoYesNo
Tomato (Solanum lycopersicum)YesNoYes
Trumpet flower (Incarvillea spp.)NoNoNo
Turnip (Brassica rapa subsp. rapa)NoNoNo
Tweedia (Oxypetalum coeruleum)NoNoNo
Twinspur (Diascia spp.)NoNoNo
Valarian (Valeriana officinalis)NoYesNo
Verbena (Verbena spp.)NoYesNo
Viola (Viola spp.)NoYesNo
Virginian stock (Malcolmia maritima)NoNoNo
Wallflower (Erysimum cheiri, syn. Cheiranthus cheiri)NoNoNo
Watermelon (Citrullus lanatus)YesNoYes
Wild garlic (Allium ursinum)NoYesNo
Wild indigo (Baptisia spp.)YesYesYes
Wishbone flower (Torenia fournieri)NoNoNo
Xeranthemum (Xeranthemum
annuum
)
NoNoNo
Yarrow (Achillea spp.)NoYesNo
Zinnia (Zinnia spp.)NoNoNo
Zucchini (Cucurbita pepo)YesNoYes