Seeds that Require Special Treatment

When growing hydroponic plants, you will need to follow the same guidelines soil-based gardeners use with seed starting. The key thing is to know what the vegetable, herb, or flower plant needs to best start from seed. In cases where seeds need complete darkness, we recommend using vermiculite to cover your seed if growing hydroponically.

Here’s a handy chart to reference before you start a plant from seed. (PDF version link available below)

Seeds that Need Light to Germinate

Alphabetized by Botanical Name | Also referenced as Common Name

Achillea species — YARROW
Acmella oleracea | Spilanthes acmella — TOOTHACHE PLANT
Ageratum Houstonianum — FLOSSFLOWER
Alyssum montamum — BASKET OF GOLD
Anethum graveolens — DILL
Antirrhinum majus — SNAPDRAGON
Aquilegia species and hybrids — COLUMBINE
Arabis species — ROCK CRESS, WALL CRESS
Artemisia vulgaris | Artemisis absinthium — WORM WOOD
Begonia species — BEGONIA
Brassica oleracea Acephala — ORNAMENTAL CABBAGE
Browallia speciosa — BROWALLIA
Campanula species —BELLFLOWER
Capicum anuum — ORNAMENTAL PEPPER
Chrysanthemum Parthenium — MATRICARIA, FEVERFEW
Chrysanthemum x superbum — SHASTA DAISY
Coleus x hybridus — COLEUS
Coreopsis grandiflora — TICKSEED
Doronicum cordatum — LEOPARD’S BANE
Eruca vesicaria sativa — ARUGULA, aka: SALAD ROCKET
Gailardia x grandiflora — BLANKET FLOWER
GerberaJamesonii hybrids — TRANSVAAL DAISY
Helichrysum bracteatum — STRAWFLOWER
Hypericum perforatum — ST. JOHNS WORT
Impatiens Wallerana — IMPATIENS
Lactuca sativa — LETTUCE
Labutaria maritima — SWEET ALYSSUM
Lynchis chalcedonica — MALTESE-CROSS
Matthiola species — STOCK
Moluccella laeves — BELLS OF IRELAND
Nepeta cataria — CATNIP
Nicotianna alata — FLOWERING TOBACCO
Papaver orientale — ORIENTAL POPPY
Petunia x hybrida — PETUNIA
Platycodon grandiflorus — BALLOON FLOWER
Pelargonium domesticum — GERANIUM
Primula species except P. sinensis —PRIMROSE
Reseda odorata — MIGNONETTE
Salvia species — SALVIA (Red flowered varieties)
Sanvitalia procumbens — CREEPING ZINNIA
Sauterne species — SAVORY
Tithonia rotundifloria — MEXICAN SUNFLOWER
Urtica dioica — STINGING NETTLE

Seeds that Need Darkness to Germinate

Alphabetized by Botanical Name | Also referenced as Common Name

Borago officinalis — BORAGE
Calendula officinalis — POT MARIGOLD
Catharanthus roseus — PERIWINKLE
Centaurea Cyanus — BACHELOR’S BUTTON
Consolida ambigua — LARKSPUR
Coriandrum sativum — CORIANDER (CILANTRO)
Delphinium species — DELPHINIUM
Foeniculum species — FENNEL
Gazania rigens — TREASURE FLOWER
Lathyrus odoratus — SWEET PEA
Myosotis species — FORGET-ME-NOT
Nemesia strumosa — NEMESIA
Palaver species except Porientale — POPPY
Phlox species — PHLOX
Primula sinensis — CHINESE PRIMROSE
Salpiglossis sinuata — PAINTED TONGUE
Schizanthus x wisetonensis — BUTTERFLY FLOWER, POOR MAN’S ORCHID
Tropaolum majus — NASTURTIUM
Verbena species — VERBENA
Viola species — VIOLA, VIOLET, PANSY

Seeds that Require Soaking before Sowing

Alphabetized by Botanical Name | Also referenced as Common Name

Abelmoschus esculentus — OKRA
Armeria maritima — THRIFT, SEA PINK
Asparagus officinalis — ASPARAGUS
Baptisia australis — BLUE INDIGO
Hibiscus species — MALLOW
Pomona species — MORNING GLORY
Lathyrus latifolius — PERENNIAL PEA
Lathyrus odoratus — SWEET PEA
Liriope Muscari — LILYTURF
Lupines species — LUPINES
Pastinaca sativa — PARSNIPS
Petroselinum crispum — PARSLEY

Seeds that Need Stratification before Sowing (Cold Treatment)

Alphabetized by Botanical Name | Also referenced as Common Name

Angelica Archangelica — ANGELICA
Aquilegia species and hybrids — COLUMBINE
Brassica oleracea Acephala — ORNAMENTAL CABBAGE
Dicentra spectabilis — BLEEDING HEART
Dictamnus albus — GAS PLANT
Helleborus niger — CHRISTMAS ROSE
Hemerocallis hybrids — DAYLILY
Lavandula angustifolia — LAVENDER
Machaeranthera tanacetifloria — TAHOKA DAISY
Phlox paniculata — PHLOX
Primula species — PRIMROSE
Trillium ovatum — WAKE-ROBIN
Trollius europaeus — GLOBEFLOWER
Viola species — VIOLA, VIOLET, PANSY

Seeds that Must be Scarified (nicked or filed) before Sowing

Alphabetized by Botanical Name | Also referenced as Common Name

Baptisa australis — WILD BLUE INDIGO, FALSE INDIGO
Hibiscus species — MALLOW
Ipomoea — MORNING GLORY
Lathyrus species — PERENNIAL and SWEET PEA
Lupinus species — LUPINES
Glycyrrhiza glabra — LICORCE
Calycanthus — SWEET SHRUB
Mimosa Linnaeus (Mimosaceae) — MIMOSA

Seeds that Need Cool Temperatures (55ºF) to Germinate

Alphabetized by Botanical Name | Also referenced as Common Name

Aubrieta deltoidea — FALSE ROCK CRESS, PURPLE ROCK CRESS
Cheiranthus Cheiri — WALLFLOWER
Dictanmnus albus — GAS PLANT
Erigeron species — MIDSUMMER ASTER, FLEABANE
Eschscholzia californica — CALIFORNIA POPPY
Heuchera sanguinea — CORALBELLS
Iberis sempervirens — CANDYTUFT
Lathyrus latifolius — PERENNIA PEA
Lathyrus odoratus — SWEET PEA
Matricaria Menziesii — BABY BLUE EYES
Palaver species — POPPY
Pentemom hybrids — BEARD-TONGUE
Phlox Drummondii — ANNUAL PHLOX
Rosmarius officinalis — ROSEMARY
Thymus species — THYME, MOTHER OF THYME

Seeds that Need Warm Temperatures (80ºF) to Germinate

Alphabetized by Botanical Name | Also referenced as Common Name

Capsicum — PEPPER

Hardy Annuals

(Seeds that may be sown outdoors in early spring as soon as soil can be worked and will not be affected by late spring frosts)
Alphabetized by Botanical Name | Also referenced as Common Name

Allium Ampelpprasum — LEEK
Allium Cepa — ONION
Anethum graveolens — DILL
Anthriscus Cerefolium — CHERVIL
Arctotis species and hybrids — AFRICAN DAISY
Beta vulgaris — BEET, SWISS CHARD
Borago officialis — BORAGE
Brassica species —BROCCOLI, BRUSSELS SPROUTS, CABBAGE, CAULIFLOWER, CHINESE CABBAGE, COLLARDS, KALE, KOHLRABI, MUSTARD, TURNIP
Centaurea Cyanus — BACHELOR’S BUTTON, CORNFLOWER
Consolida ambigua — LARKSPUR
Coriandrum sativum — CORIANDER (CILANTRO)
Daucus Carota var. sativus — CARROT
Eruca vesicaria — ROCKET
Eschscholzia californica — CALIFORNIA POPPY
Gypsophila species — BABY’S BREATH
Latuca sativa — LETTUCE
Lepidium sativum — GARDEN CRESS
Lobularia maritim — SWEET ALYSSUM
Machaeranthera tanacetifolia — TAHOKA DAISY
Matricaria recutita — CHAMOMILE
Mentzelia Menziessii — BABY BLUE EYES
Origanum Majorana — MARJORAM
Pastinaca sativa — PARSNIPS
Petroselinum crispum — PARSLEY
Phlox Drummondii — ANNUAL PHLOX
Pisum sativum — PEA
Raphanus sativus — RADISH
Reseda odorata — MIGNONETTE
Spinacia oleracea — SPINACH