O to Z
Oenothera acaulis, argilicola, berlandierii, biennis, caespitosa, elata, fruticosa, kunthiana, laciniata, odorata, pallida, perennis, pilosella, rhombipetala, rosea, speciosa, tetragona, and versicolor, and aff. macroscles, Sow at 20ºC (68ºF), germinates in about two wks
Oenothera erythrosepala , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Oenothera macrocarpa, missouriensis, and syrticola , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Ononis rotundifolia, and spinosa , Scarify seed, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Onopordum acanthium , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Onosma arenaria, rigida, and stellulata , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Opuntia fragilis, humifusa, phaeacantha, and polyacantha , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination , recycle
Origanum vulgare , Sow at 20ºC (68ºF), germinates in about two wks
Ornithogalum pyrenaicum, and umbellatum , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Orobanche fasiculata , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Osteospermum jucundum , Sow at 20ºC (68ºF), germinates in less than two wks
Ourisia glandulosa , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Oxyria digyna , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Oxytropis campestris, lapponica, and purpurea , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Oxypolis rigidor , Sow at 20ºC (68ºF), germinates in less than two wks
Paeonia anomala, delavayi, lactiflora, lutea, mascula, mlokosewitschii, mollis, officinalis, peregrina, suffruticosa tenuifolia, veitchii, and wittmanniana , Impervious seed coats. Shake in dry sharp sand or nick carefully with a file. Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear
Panax ginseng , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Pancratium maritimum , Sow under thin cover at 20ºC (68ºF) in light, if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Panicum lanuginosum, leibergii, oligosanthes, perlongum, praecocius, and virgatum , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Papaver alpinum, atlanticum, kerneri, lateritium, nudicaule, orientale, pilosum, and rhaeticum, Sow at 20ºC (68ºF), germinates in less than two wks do not cover
Papaver alboroseum, and miyabeanum, Sow at 20ºC (68ºF), germination slow
Papaver burseri, radicatum, rupifragum, sendtneri, and triniifolium , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks do not cover
Papaver spicatum , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Paradisea liliastrum, and lusitanica , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Pardancanda norrissii , Sow under very thin cover at 20ºC (68ºF) in light, germination slow
Paris quadrifolia , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Parnassia palustris , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Paronychia kapela , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Parthenium integrifolium , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 12 wks, then return to 20ºC (68ºF) for germination
Patrinia gibbosa, and scabiosifolia, Sow at -4 to +4ºC (24-39ºF) for 2-4 wks, then return to 20ºC (68ºF) for germination, short viable
Patrinia triloba , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Pedicularis canadensis , Sow at 20ºC (68ºF), germinates in less than two wks
Pedicularis procera , Sow at 20ºC (68ºF), germinates in less than two wks
Pelargonium endlicherianum , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Peltiphyllum peltatum, Sow at 22ºC (71ºF) for 6 wks or more. Move to -4 to +4ºC (24-39ºF) for 6-8 wks. Then raise the temperature to 10ºC (50ºF). If no germination in 4-6 wks, repeat the cycle from the beginning. If the warm/cold cycles were not long enough, a new warm/cold cycle is needed.
Peltoboykinia tellimoides, and watanabei, Sow at 22ºC (71ºF) for 6 wks or more. Move to -4 to +4ºC (24-39ºF) for 6-8 wks. Then raise the temperature to 10ºC (50ºF). If no germination in 4-6 wks, repeat the cycle from the beginning. If the warm/cold cycles were not long enough, a new warm/cold cycle is needed
Pennisetum alopecuroides, Sow at 22ºC (72ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Pennisetum compressum, orientale, and setaceum , Sow at 22-24ºC (71-75ºF), germination in less than 2 weeks , Note that P. setaceum rubra is not germinable.
Penstemon species, see separate database
Periploca graeca , Sow at 4ºC (40ºF) for 4-8 wks, move to 20ºC (68ºF) for germination
Perovskia atriplicifolia , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Petalostemum candidum, purpureum, and villosum , Sow at 20ºC (68ºF), germination slow
Petasites albus, and hybridus , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Petrocoptis glaucifolia , Sow at 20ºC (68ºF), germination slow
Petrophytum caespitosum , Sow at 20ºC (68ºF), germination slow
Petrorhagia saxifraga , Sow at 20ºC (68ºF), germinates in less than two wks
Peucedanum officinale, ostruthium, and verticillare , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Phacelia sericea , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Phalaris arundinacea, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Phlomis cashmeriana, fruticosa, russeliana, and samia , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Phlomis tuberosa , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Phlox glaberrima v. interior, and pilosa , Sow immediately outdoors. Short viability seed will germinate in the spring.
Phlox x arendsii, and paniculata , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Phragmites australis , Sow at 22ºC (72ºF) in muddy compost
Phuopsis stylosa , Sow at 20ºC (68ºF), germination slow
Phygelius aequalis, and capensis , Sow at 22-24ºC (71-75ºF), germ. in less than 2 weeks
Physalis franchetii , Wash seeds several times, Sow at 22-24ºC (71-75ºF), germinates in less than two wks
Physalis subglabrata, and virginiana , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 22ºC (72ºF) for germination
Physochlaina orientalis , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Physoplexis comosa , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Physostegia virginiana , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination not true to type
Phyteuma humile, orbiculare, sibiricum, and spicatum , Surface sow at 20ºC (68ºF) in light, if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks, recycle
Phyteuma hemisphaericum, nigrum, and scheuchzeri , Surface sow at 20ºC (68ºF) in light, germination slow
Phytolacca acinosa, and americana , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Phytolacca octandra , Sow at 20ºC (68ºF), germinates in less than two wks
Pimpinella saxifraga , Sow at 20ºC (68ºF), germinates in about two wks
Plantago lanceolata, major, and nivalis , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Platycodon apoyama, and grandiflorus , Sow at 20ºC (68ºF), germination slow
Plumbago capensis , Sow at 23ºC (73ºF), germinates in less about 2 wks
Poa alpina, and chaixii , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Poa palustris , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Podophyllum hexandrum, and peltatum , Pour hot water over seeds, let soak 1-2 days until swelling noticeable. Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination Short viable
Polemonium carneum , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Polemonium boreale, caeruleum, cashmirianum, chartaceum, delicatum, foliosissimum, pauciflorum, reptans, x rickharsonii, and viscosum , Sow at 20ºC (68ºF), germination slow
Polygonatum canaliculatum, humile, latifolium, multiflorum, odoratum, and verticillatum , Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear
Polygonum aubertii , Sow at +4ºC (39ºF) for germ. in about 7 weeks
Polygonum bistorta , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Polygonum capitatum , Sow at 20ºC (68ºF), germination slow
Polygonum filiforme, viviparum, and weyrichii , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Polytaenia nuttallii , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Potentilla alba, argentea, argyrophylla, atrosanguinea, calabra, concolor, crantzii, fragiformis, gracilis, megalantha, nepalensis, rupestris, and thurberi , Sow at 20ºC (68ºF), germination slow
Potentilla arguta, canadensis, caulescens, erecta, and fruticosa , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Potentilla hyparctica, neumanniana, palustris, speciosa, and tridentata , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Potentilla multifida, and pensylvanica , Sow at 20ºC (68ºF), germinates in less than two wks
Potentilla aurea, heptaphylla, and recta , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Pratia angulata, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Prenanthes alba, aspera, and racemosa , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Primula alpicola, beesiana, x bullesiana, bulleyana, candelabra hybrids, cockburniana, pubescens, pulverulenta, and waltonii, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Primula auricula, burmanica, chungensis, x chunglenta, elatior, hirsuta, integrifolia, japonica, juliae, pedemontana, poissonii, rosea, sieboldii, sinopurpurea, smithiana, veris, viscosa, and vulgaris , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination s
Primula capitata, cortusoides, florindae, polyneura, x pubescens, saxatilis, sikkimensis, and sinopurpurea, Surface sow at 20ºC (68ºF), germination slow
Primula denticulata, farinosa, halleri, nutans, polyantha hybrids, and viallii, Surface sow at 20ºC (68ºF), germinates in less than two wks
Primula frondosa, luteola, secundiflora, scotica , and verticillata, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Primula juliae , Sow at 22ºC (71ºF) for 6 wks or more. Move to -4 to +4ºC (24-39ºF) for 6-8 wks. Then raise the temperature to 10ºC (50ºF). If no germination in 4-6 wks, repeat the cycle from the beginning. If the warm/cold cycles were not long enough, a new warm/cold cycle is needed.
Prunella grandiflora, laciniata, vulgaris, and webbiana, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Prunus prostrata , Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear
Psoralea argophylla, esculenta, and tenuiflora, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Pterocephalus perennis, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Ptilotrhchum pyrenaicum , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Ptilotrichum spinosum, Sow at 20ºC (68ºF), germination slow
Pulmonaria mollissima, officinalis, rubra, and saccarata , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Pulsatilla alba, albana, alpina, ambigua, dahurica, grandis, halleri, montana, occidentalis, patens, pratensis, serotina, and vernalis , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Pulsatilla vulgaris , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Punica granatum , Sow at 23ºC (73ºF), germinates in about two wks
Pycnanthemum incanum, and pilosum , Sow at 20ºC (68ºF), germinates in about two wks
Pycnanthemum tenuifolium, and virginianum , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF)
Ramonda myconi, and nathaliae , Surface sow at 20ºC (68ºF) in light, if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Ranunculus aconitifolius , amplexicaulis, buchananii, fascicularis, flammula, glacialis, gramineus, haastii, insignis, lyallii, nivicola, pachyrrhizus, parnassifolius, pyrenaeus, romboides, sericophyllus, and thora, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to 5ºC (23ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination Short viable
Raoulia australis, subserica, and tenuicaulis , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Ratibida columnaris, columnifera, and pinnata , Sow at 20ºC (68ºF), germinates in less than two wks
Rehmannia elata , Sow at 23ºC (73ºF), germinates in about two wks
Rheum australe, and palmatum , Sow at 20ºC (68ºF), germinates in less than two wks
Rhexia virginica , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Rhodiola rosea , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination do not cover
Rhodiola rhodantha, and semenovii , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks do not cover
Rhododendron camtschaticum, and ferrugineum, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Rodgersia henrici hybrids, and podophylla , Sow at 20ºC (68ºF), germination slow do not cover
Rodgersia aesculifolia, pinnata, sambucifolia, and tabularis, Sow at 20ºC (68ºF), germ. in less than two wks do not cover
Romneya coulteri, and trichocalyx, Sow at Max. 5ºC (41ºF), germination irregular, often several months very difficult. Try GA3 or store seeds in layers of moist sand in the shade. Check seeds regularly every spring, and sow them all as soon as radicles appear.
Roscoea alpina , Impervious seed coats. Shake in dry sharp sand or nick carefully with a file. Sow at Max. 5ºC (41ºF), germination irregular, often several months
Roscoea auriculata, cautleoides, purpurea, and scillifolia, Sow at 22-24ºC (71-75ºF), germination in about 2 weeks
Rosmarinus officinalis , Sow at 20ºC (68ºF), germinates in less than two wks thin cover, needs light
Rudbeckia fulgida, hirta, and maxima , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Rudbeckia laciniata, nitida, occidentalis, and purpurea , Sow at 20ºC (68ºF), germination slow
Rudbeckia subtomentosa, and triloba , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Ruellia humilis , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Rumex acetosella, and sanguineus , Sow at 20ºC (68ºF), germinates in less than two wks
Rumex flexuosus , Sow at 20ºC (68ºF), germination slow
Rumex hydrolapathum , Sow at 22ºC (72ºF) in muddy compost
Ruscus aculeatus , Impervious seed coats. Shake in dry sharp sand or nick carefully with a file. Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear
Ruta graveolens , Sow at 20ºC (68ºF), germinates in less than two wks
Sabatia angularis , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Saccharum ravennae , Extract seeds from pods, then sow at 20ºC (68ºF), germinates in less than two wks
Sagina subulata , Surface sow at 20ºC (68ºF) in light, germinates in less than two wks
Sagittaria sagittifolia , Sow at 22ºC (72ºF) in muddy compost
Salvia farinacea , forskaohlei, miltiorrhiza, officinalis, sclarea, and x superba , Sow at 20ºC (68ºF), germinates in less than two wks
Salvia amplexicaulis, argentea, glutinosa, hians, jurisicii, lavandulifolia, lyrata, nemorosa, pratensis, przewalskii, recognita, transylvanica, and verticillata, Sow at 20ºC (68ºF), germination slow
Salvia ringens , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Sanguinaria canadensis , Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear short viable
Sanguisorba canadensis, hakusanensis, obtusa, officinalis, parviflora, and tenuifolia, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Sanguisorba minor , Sow at 20ºC (68ºF), germinates in less than two wks thin cover, needs light
Sanicula europaea , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Santolinia chamaecyparissus, and rosmarinifolius , Sow at Max. 5ºC (41ºF), germ. irregular, often several months
Saponaria ocymoides , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Saponaria caespitosa, lutea, officinalis, and pumila , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Sarcococca ruscifolia , Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear short viable
Satureja montana , Sow at 20ºC (68ºF), germination slow
Saxifraga aizoides, aspera, biflora , burseriana, cochlearis, cotyledon, cuneifolia, diapensioides, exarata, ferdinandi-coburgi rhodopea, granulata, grisebachii, hostii, longifolia, manschuriensis, marginata, oppositifolia, paniculata, sachalinensis, sedoides, sempervivum, spathularis, stellaris, stribrnyi, umbrosa, and x urbium, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination do not cover
Saxifraga pennsylvanica , Surface sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Saxifraga x arendsii, mutata, and rotundifolia, Sow at 20ºC (68ºF), germination slow do not cover
Scabiosa caucasica , Sow at 22-24ºC (71-75ºF), germination in about 2 weeks
Scabiosa columbaria, graminifolia, japonica, lucida, and ochroleuca, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Schivereckia doerfleri , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Schivereckia podolica , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Schizachyrium scoparium , Sow at 20ºC (68ºF), germinates in less than two wks
Scilla bifolia , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Scirpus holoschoenus, lacustris, and tabernaemontani , Sow at 22ºC (72ºF) in muddy compost
Scirpus mucronatus, and sylvaticus, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Scleranthus uniflorus , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Scopolia carniolica , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Scrophularia grandiflora , Sow at 20ºC (68ºF), germination slow
Scrophularia nodosa , Sow at Max. 5ºC (41ºF), germ. irregular, often several months
Scutellaria alpina, baicalensis, indica, orientalis, parvula, pontica, and velenovskyi, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Scutellaria galericulata , Wash seeds several times, Sow at +4ºC (39ºF) for 6 wks, move to 16ºC (60ºF) for germ.
Scutellaria incana , Sow at Max. 5ºC (41ºF), germ. irregular, often several months
Scutellaria altissima , Sow at 20ºC (68ºF), germination slow
Sedum acre, aizoon, forsterianum, rupestre, and spurium, Sow at 20ºC (68ºF), germinates in less than two wks do not cover
Sedum anacampseros, floriferum, kamtschaticum, lanceolatum, oreganum, pulchellum, and reflexum, Sow at 20ºC (68ºF), germination slow do not cover
Sedum album, ewersii, spathulifolium, and ternatum, Sow at Max. 5ºC (41ºF), germination irregular, often several months do not cover
Sedum populifolium, and telephium , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination do not cover
Selinum carvifolia , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Semiaquilegia adoxiodes, and ecalcarata, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Sempervivum arachnoideum, calcareum, grandiflorum, montanum, and tectorum, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks do not cover
Senecio aureus, incanus, integrifolius, nemorensis, pauperculus, and plattensis, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germ.
Senecio cineraria , Sow at 20ºC (68ºF), germinates in less than two wks
Senecio doronicum, Sow at -4 to +4ºC (24-39ºF) for erratic germination
Senna hebecarpa , Sow at 20ºC (68ºF), germinates in less than two wks
Serratula tinctoria , Sow at 20ºC (68ºF), germination slow
Seseli elatum, gracilis, montanum, and rigida, Sow at 20ºC (68ºF), germination irregular
Seseli gummiferum, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Sesleria caerulea, heuffleriana, nitida, and sadlerana, Sow at -4 to +4ºC (24-39ºF) for erratic germination
Sidalcea candida, hybrida, malvaflora, and neomexicana, Sow at 20ºC (68ºF), if no germination in 2 wks, move to -4 to +4ºC (24-39ºF) indefinitely. .
Sideritis syriaca , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Silene alpestris, apetalum, bellidoides, fimbriata, orientalis, and schafta, Sow at 20ºC (68ºF), germinates in less than two wks
Silene acaulis, asterias, californica, caroliniana, coeli-rosea, maritima, pusilla, regia, waldsteinii, and zawadskii, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Silene alba, caryophylloides, dioica, hookerii, nutans, saxifraga, scouleri, uniflora, vallesia, and vulgaris, Sow at 20ºC (68ºF), germination slow
Silene elisabethae, and vallesia, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Silphium dentata, integrifolium, laciniatum, and perfoliatum, Sow at 4ºC (40ºF) for 12 wks, move to 20ºC (68ºF) for germination
Silphium terebinthinaceum , Sow at 20ºC (68ºF), germination slow
Silybum marianum, Sow at 20ºC (68ºF), germinates in less than two wks
Sisyrinchium albidum, angustifolium, bellum, californicum, campestre, douglasii, montanum, and striatum, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Smilacina racemosa , Slow germinator - up to a year or more. Store seeds in layers of moist sand in the shade. Check seeds regularly in the spring, and sow them all as soon as radicles appear
Smilacina stellata , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Smyrnium perfoliatum , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Solanum dulcamara , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Soldanella alpina, carpatica, montana, and pusilla, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for slow germination very slow-growing the first 2-3 years
Solidago altissima, caesia, canadensis, cutleri, gigantea, glomerata, graminifolia, juncea, missouriensis, multiradiata, nemoralis, pinetorum, puberula, remota, riddellii, rigida, roanesis, sempervirens, speciosa, sphacelata, uliginosa, and virgaurea, Sow at 20ºC (68ºF), germinates in less than two wks
Solidaster luteus (Aster x Solidago) , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination Very poor germination
Sorghastrum nutans , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Sparganium erectum , Sow at 22ºC (72ºF) in muddy compost for 6 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, then allow temperatures to raise gradually.
Spartina pectinata , Sow at 22ºC (72ºF) in muddy compost for 6 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, then allow temperatures to raise gradually.
Spergularia rubra , Sow at 20ºC (68ºF), germination slow
Sphaeralcea coccinea , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Sphenopholis intermedia , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Spiranthes cernua , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Spodiopogon sibiricus , Sow at 20ºC (68ºF) in light, germinates in about two wks
Sporobolus asper, cryptandrus, and heterolepsis, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Stachys byzantina, coccinea, lanata, and olympica , Sow at 20ºC (68ºF), germinates in less than two wks
Stachys grandiflora, monnieri, and officinalis , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Stachys palustris, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Stellaria holostea , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Sternbergia candida, clusiana, and fischeriana , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Stipa barbata, calamagrostis, grandis, pennata, spartea, tenuissima, and viridula, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Stipa extremiorientalis, pulcherrima, tenuissima, and ucrainica , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Stipa capillata, and gigantea , Sow at 20ºC (68ºF), germination slow
Stokesia laevis , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) indefinitely.
Stylophorum diphyllum, and lasiocarpum, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Succisa pratensis , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Swertia kingii, and perennis, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Symphyandra armena, hofmanii, pendula, wanneri, and zanzegur, Sow at 20ºC (68ºF) in light, germinates in less than two wks
Symphytum officinale, and tuberosum , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Talinum okanoganense , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Talinum rugospermum , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Tanacetum balsamita, cineariifolium, coccineum, corymbosum, demetrii, huronense, niveum, parthenium, and vulgaris, Sow at 20ºC (68ºF) in light, if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks thin cover
Taraxacum officinale , Sow at 20ºC (68ºF), germination slow
Telekia speciosa , Sow at 20ºC (68ºF), germinates in less than two wks
Tellima grandiflora , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Tephrosia virginiana , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Tetragonolobus maritimus , Sow at 20ºC (68ºF), if no germ. in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Teucrium canadense, flavum, and nassilense , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Teucrium chamaedrys, and montanum, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Teucrium hyrcanicum , Sow at +4ºC (39ºF) for 8 wks, then move to coldframe for oscillating temps
Teucrium polium, and scorodonia , Sow at 20ºC (68ºF), germinates in about two wks
Thalictrum aquilegifolium, chelidonii, dasycarpum, dipterocarpum, flavum, foetidum, lucidum, minus, revoltum, and rochebrunianum , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Thamnocalamus spathaceus , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Thaspium trifoliatum , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Themeda triandra japonica , Sow at 20ºC (68ºF), germination slow
Thermopsis caroliniana, lanceolata, and montana , Impervious seed coats. Shake in dry sharp sand or nick carefully with a file. Soak for 1-2 days. Sow at 20ºC (68ºF), germinates in about 2 weeks Short viable
Thlaspi rotundifolium , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Thymus pulegioides, serpyllum, and vulgaris, Sow at 20ºC (68ºF), germinates in about two wks
Tiarella polyphylla, and wherryi , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Tofieldia calyculata , Sow at 20ºC (68ºF), germination slow
Tofieldia glutinosa , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Tolmiea menziesii , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Townsendia florifera, grandiflora, and incana, Sow at 20ºC (68ºF), germinates in about two wks
Trachelium caeruleum , Sow at 20ºC (68ºF), germinates in less than two wks
Tradescantia x andersoniana, ohiensis, and virginiana, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Trichostema dichotoma , Sow at 20ºC (68ºF), germinates in less than two wks
Tricyrtis hirta, latifolia, and maculata, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Tricyrtis macropoda , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Trifolium alpinum , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Trifolium ochroleucum, and rubens , Sow at 20ºC (68ºF), germination slow
Trillium cernuum, cumeatum, erectum, grandiflorum, luteum, sessile, and undulatum, Sow immediately outdoors. Short viability seed will germinate in the spring or in the spring of subsequent years. Very short viable. Store seed cold and moist. Sow fresh.
Tripterospemum marianum , Sow at 20ºC (68ºF), germinates in less than two wks
Trisetum flavescens , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Trollius acaulis, altaicus, asiaticus, chinensis, x cultorum, europaeus, laxus, pumilus, and yunnanensis, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -6 to -7ºC (19-21ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Tropaeolum ciliatum, and speciosum, Impervious seed coats. Shake in dry sharp sand or nick carefully with a file. Soak seeds 1-2 days or until swelling noticeable. Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination Short viable
Tulipa kaufmanniana, pulchella, sprengeri, sylvestris, tarda, turkestanica, and urumiensis , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Typha angustifolia, latifolia, laxmannii, and shuttleworthii, Sow in muddy compost at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) gradually, for germination
Unicinia rubra , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Vaccinium macrocarpon, and myrtillus, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Vaccinium vitis-idaea , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Valeriana ciliata, and officinalis, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Vania campylophylla , Sow at 20ºC (68ºF), germinates in less than two wks grow on in 10-15ºC (50-59ºF) in good light
Veratrum album, californicum, nigrum, and viride, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -6 to -7ºC (19-21ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Verbascum blattaria, bombyciferum, chaixii, densiflorum, hybridum, longifolium, olympicum, phoeniceum, roripifolium, and thapsus, Sow at 20ºC (68ºF), germinates in less than two wks cover thin
Verbascum nigrum , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Verbena bonariensis, rigida, and stricta, Sow at -4 to +4ºC (24-39ºF) for 4 wks, move to 20ºC (68ºF)for germination
Verbena hastata , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Verbena tenuisecta , Sow at 20ºC (68ºF), germination slow
Verbesina alternifolia, virginica , Sow at 20ºC (68ºF), if no germ. in 4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Vernonia altissima, baldwinii, crinita, fasciculata, missurica, noveboracensis, and novaborensis, Sow at 4ºC (40ºF) for 12 wks, move gradually to 20ºC (75ºF) for germination
Veronica austriaca, fruticans, fruticulosa, gentianoides, gutheriana, officinalis, prostrata, satureioides, schmidtiana, and virginica, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks thin cover, needs light
Veronica incana, longifolia, spicata, subsessilis, teucrium, and urticifolia, Sow at 20ºC (68ºF), germinates in less than two wks thin cover, needs light
Veronica repens , Sow at 20ºC (68ºF), germination slow
Veronicastrum sibiricum, virginica, and virginicum , Sow at 20ºC (68ºF) in light, if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks Do not cover
Vicis americana , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Viguiera dentata , Sow at 20ºC (68ºF), germination slow
Viguiera multiflora , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Vincetoxicum forrestii, and hirundinaria , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Viola cornuta, Sow at 20ºC (68ºF), germinates in less than two wks
Viola coreana, mirabilis, nigra, and pedatifida , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Viola elatior, jooi, labradorica, obliqua, pumila, reichenbachiana, rupestris, and triloba, Sow at Max. 5ºC (41ºF), germination irregular, often several months
Viola lanceolata, papilionacea, and sagittata, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Viola odorata, pedata, and sororia, Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Vitaliana primuliflora , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Vitex agnus-castus , Sow at 22-24ºC (71-75ºF), germination in less than 2 weeks
Vitis vulpina , Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Vulpia octoflora, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination
Wahlenbergia akaroa, albomarginata, and congesta , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Wyethia helianthoides , Sow at Max. 5ºC (41ºF), germination irregular, often several months
Wulfenia bullii , and carinthiaca, Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 6-12 wks , move to 5-12ºC (41-53ºF) for germination do not cover
Xerophyllum tenax , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to -4 to +4ºC (24-39ºF) for 4-6 wks, move to 5-12ºC (41-53ºF) for germination
Yucca baccata, filamentosa, and glauca, Sow at 22-24ºC (71-75ºF), germination in less than 2 weeks
Zigadenus elegans, nuttallii, and venosus, Sow at 20ºC (68ºF), germination slow
Zizea aptera , and aurea, Sow at -4 to +4ºC (24-39ºF) for 12 wks, move to 20ºC (68ºF) for germination