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
Seedlings that Resent Transplanting (Note: For Soil based; Rockwool starts should transfer okay)
(Sow seeds where they are to grow or in individual pots)
Alphabetized by Botanical Name | Also referenced as Common Name
- Anethum graveolens — DILL
- Anthriscus Cerefolium — CHERVIL
- Beta vulgaris — SWISS CHARD, BEET
- Borage officinalis — BORAGE
- Brassica species — MUSTARD, RUTABAGA, TURNIP
- Carum Carvi — CARAWAY
- Coriandrum sativum — CORIANDER (CILANTRO)
- Daucus Carota — CARROT
- Eruca vesicaria — ROCKET
- Eschscholozia califfornica — CALIFORNIA POPPY
- Foeniculum species — FENNEL
- Lavatera hybrids — TREE MALLOW
- Linum species — FLAX
- Lupines species — LUPINE
- Nigella damascena — LOVE-IN-A-MIST
- Palaver species — POPPY
- Pastinaca sativa — PARSNIP
- Petroselinum crispum — PARSLEY
- Phlox Drummondii — ANNUAL PHLOX
- Pimpinella Anisum — ANISE
- Pisum sativum — PEA
- Sanvitalia procumbens — CREEPING ZINNIA
- Sesamum indicum — SESAME
- Spinacia oleracea — SPINACH
- Trachymene coerulea — BLUE LACE FLOWER
- Tropaeolum majus — NASTURTIUM
- Zea Mays — CORN
Seeds that Should be Sown as Soon as Possible
(They are not long-lived and should not be stored)
Alphabetized by Botanical Name | Also referenced as Common Name
- Angelica Archangelica — ANGELICA
- Chrysanthemum coccineum — PYRETHERUM, PAINTED DAISY
- Delphinium species — DELPHINIUM
- Dimorphotheca sinata — CAPE MARIGOLD
- Geranium sanguineum — CRANESBILL
- Gerbera Jamesonii hybrids — TRANSVAAL DAISY
- Kochia scoparia — BURNING BUSH
- Salvia splendens — SCARLET SAGE
Seeds That Will Germinate With or Without Exposure to Light
Alphabetized by Botanical Name | Also referenced as Common Name
- Asteris — Aster
- Cole sata — Cole Crops
- Celosia cristata — Celosia
- Cosmos bipinnatus — Cosmos
- Cucumis — Melons
- Cucumis — Cucumbers
- Cucurbita — Squash
- Dianthus caryophyllus — Dianthus
- Lobularia maritima — Alyssum
- Pingit vaccinia caltha — Marigold
- Piperis — Pepper
- Solanum lycopersicum — Tomato
- Solanum melongena— Eggplant
- Zinnia elegans — Zinnia