Specific requirements

Genus Temp Time How to sow
Abutilon 16ºC-21ºC (61ºF-70ºF) 30-90 days Lightly cover seed and use well drained compost
Acaena 5ºC-12ºC (41ºF-53ºF) up to 1 year Lightly cover seed and use well drained compost
Requires warm/cold/warm stratification
Germination may be slow and erratic
Actaea 13ºC-16ºC (55ºF-61ºF) up to 1 year Germination may be slow or erratic
Requires warm/cold/warm stratification
Agastache 10ºC-16ºC (50ºF-61ºF) 30-90 days Sow in spring. Lightly cover seeds
Alcea 16ºC-21ºC (61ºF-70ºF) up to 90 days Lightly cover seeds
Amaranthus 21ºC-24ºC (70ºF-75ºF) up to 90 days Lightly cover seeds
Ammi 16ºC-21ºC (61ºF-70ºF) 7-21 days Can be sown in spring or autumn into well drained compost.
Amorpha 10ºC-16ºC (50ºF-61ºF) 30-120 days Soak seeds in warm water for 12 hours. Sow 2mm deep 
Amsonia 13ºC-16ºC (55ºF-61ºF) up to 90 days Lightly cover seeds
Anemanthele 18ºC-21ºC (64ºF-70ºF) 30-90 days Use well drained compost
Anemone 10ºC-13ºC (50ºF-55ºF) up to 1 year Sow in autumn or spring
Requires a period of cold moist stratification
Lightly cover seeds
Angelica 10ºC-13ºC (50ºF-55ºF) 30-90 days Lightly cover seeds
Anthriscus 10ºC-13ºC (50ºF-55ºF) up to 30 days Usually does best if sown in situ
Lightly cover seed
Requires a period of cold, moist stratification
Armeria 16ºC-21ºC (61ºF-70ºF) 30-90 days Sow spring or autumn
Soak seeds overnight in warm water prior to sowing
Lightly cover seeds with compost
Aruncus 13ºC-18ºC (55ºF-64ºF) may take more than 1 year Sow in autumn
Needs a period of cold moist stratification
Asphodeline 16ºC-21ºC (61ºF-70ºF) 30-90 days Lightly cover seeds
Species resents root disturbance
Asphodelus 16ºC-21ºC (61ºF-70ºF) 30-90 days Lightly cover seeds
Species resents root disturbance
Astrantia 18ºC-21ºC (64ºF-70ºF) up to 1 year Needs a period of warm/cold/warm moist stratification
Leave seeds uncovered when sown
Requires light to germinate
Atriplex 13ºC-18ºC (55ºF-64ºF) up to 30 days Requires light to germinate
Baptisia 18ºC-21ºC (64ºF-70ºF) up to 30 days Pre-soak seeds in hot water for 12 hours
Requires a free draining compost
Germination can be erratic
Berkheya 15ºC-21ºC (59ºF-70ºF) more than 90 days Lightly cover seeds
Requires light to germinate
Betonica 13ºC-18ºC (55ºF-64ºF) more than 90 days Sow in late spring or autumn
Requires a period of cold moist stratification
Calendula 13ºC-18ºC (55ºF-64ºF) up to 30 days Can be sown in situ in spring or autumn
Sow 6mm deep
Callistemon 16ºC-21ºC (61ºF-70ºF) more than 90 days Leave seeds uncovered when sown
Campanula 16ºC-21ºC (61ºF-70ºF) up to 90 days Leave seeds uncovered when sown
Requires light to germinate
Campsis 16ºC-21ºC (61ºF-70ºF) up to 30 days Sow in spring
Chilling may improve germination
Catalpa 16ºC-21ºC (61ºF-70ºF) up to 30 days Soak seeds for 24 hours prior to sowing
Surface sow as light is needed for germination
Good ventilation required to prevent damping off
Cenolophium 13ºC-18ºC (55ºF-64ºF) up to 1 year Leave seeds uncovered when sown
Requires light to germinate
Centaurea 16ºC-21ºC (61ºF-70ºF) up to 30 days Sow in spring, covering seeds lightly
Centranthus 15°C-20°C (59°F-68°F) up to 30 days Sow 2mm deep in spring
Cephalaria 13ºC-18ºC (55ºF-64ºF) up to 90 days Sow 5mm deep in spring
Chelone 13ºC-16ºC (55ºF-61ºF) 30-90 days Lightly cover seeds 
Needs good drainage
Chusquea 20°C (68°F) 3 to 6 months Surface sow and do not allow to dry out
Cichorium 10ºC-16ºC (50ºF-61ºF) up to 30 days Sow in spring
Cleome 18ºC-24ºC (64ºF-75ºF) up to 30 days Surface sow seeds
Germination seems to improve with warm days and cooler nights
Cladrastis 16ºC-21ºC (61ºF-70ºF) up to 1 year Sow in autumn
Soak seeds in hot water, leaving to stand for 24 hours
Needs a period of cold moist stratification
Coriandrum 10ºC-16ºC (50ºF-61ºF) up to 30 days Resents root disturbance so sow direct
Sow 10mm deep
Cordyline 18ºC-22ºC (64ºF-72ºF) 60-90 days Sow 2mm deep in late spring. Do not overwater as seeds are susceptible to damping off
Coreopsis 18ºC-21ºC (64ºF-70ºF) up to 25 days Sow in early spring
Lightly cover seeds
Crocus 10ºC-16ºC (50ºF-61ºF) up to 1 year Species resents root disturbance - sow directly into suitable container
Requires a period of cold moist stratification
Cyclamen 13ºC-16ºC (55ºF-61ºF) up to 1 year Pre-soak seed in cold water. Requires a period of cold moist stratification and may need two chilling periods to break double dormancy. Once sown keep moist and dark
Datisca 18ºC-21ºC (64ºF-70ºF) up to 30 days Surface sow as light is needed for germination
May need a period of cold moist stratification
Daucus 10ºC-16ºC (50ºF-61ºF) 10-20 days Sow direct and cover seed lightly. Can be sown either February to April or August to September.
Deinanthe 18ºC-21ºC (64ºF-70ºF) 30-90 days Leave seeds uncovered when sown
Deschampsia 10ºC-16ºC (50ºF-61ºF) up to 30 days Sow in early spring or autumn, lightly covering seeds
Germination can be erratic
Dianthus 16ºC-18ºC (61ºF-64ºF) up to 90 days Lightly cover seeds
Needs good drainage
Dicentra 10ºC-16ºC (50ºF-61ºF) up to 1 year Lightly cover seeds
Requires a period of cold moist stratification
Dierama 18ºC-21ºC (64ºF-70ºF) up to 1 year Lightly cover seeds
Chilling may improve germination
Germination can be erratic
Digitalis 13ºC-16ºC (55ºF-61ºF) 30-90 days Leave seeds uncovered when sown
Requires light to germinate
Dryas 16ºC-21ºC (61ºF-70ºF) up to six months Sow in autumn, lightly covering seeds
Requires a period of cold moist stratification
Eccremocarpus 16ºC-21ºC (61ºF-70ºF) up to 90 days Lightly cover seeds
Germination can be erratic
Echinacea 18ºC-24ºC (64ºF-75ºF) 30-90 days Leave seeds uncovered when sown
Erigeron 16ºC-21ºC (61ºF-70ºF) up to 90 days Leave seeds uncovered when sown
Erodium 16ºC-21ºC (61ºF-70ºF) up to 30 days Sow in spring or autumn, just covering seed as light is required for germination
Eryngium 10ºC-16ºC (50ºF-61ºF) up to 90 days Sow in autumn, lightly covering seeds
Requires a period of cold moist stratification
Germination can be slow and irregular, so pot on each seedling as emerges
Erysimum 16ºC-18ºC (61ºF-64ºF) up to 30 days Sow late summer for spring flowering or late winter for autumn flowering. Lightly cover seeds
Eschscholzia 16ºC-18ºC (61ºF-64ºF) up to 90 days Best sown direct in spring as resents root disturbance
Euphorbia 15ºC-18ºC (58ºF-64ºF) up to 90 days Lightly cover seeds
If seed does not germinate it may need a period of cold moist stratification 
Germination may be slow and irregular
Eurybia 15ºC-18ºC (59ºF-64ºF) up to 90 days Surface sow as seed needs light to germinate. Requires a period of cold moist stratification
Ferula 10ºC-16ºC (50ºF-61ºF) up to 1 year Requires a period of cold moist stratification
Germination may be slow and irregular
Foeniculum 13ºC-18ºC (55ºF-64ºF) up to 30 days Best sown direct in spring as resents root disturbance
Sow 10mm deep
Francoa 13ºC-16ºC (55ºF-61ºF) up to 30 days Lightly cover seeds
Fritillaria 13ºC-18ºC (55ºF-64ºF) up to 1 year Sow in autumn, lightly covering seeds
Requires a period of cold moist stratification
Gazania 15ºC-18ºC (59ºF-64ºF) up to 30 days Sow in spring
Sow 5mm deep
Gentiana 10ºC-13ºC (50ºF-55ºF) up to 1 year Lightly cover seeds
Requires a period of cold moist stratification
Geum 13ºC-18ºC (55ºF-64ºF) up to 90 days Sow in spring
Lightly cover seeds
Gillenia 15ºC-18ºC (59ºF-64ºF) 30-90 days Requires a period of cold moist stratification
Glycyrrhiza 15ºC-18ºC (59ºF-64ºF) 30-90 days Pre-soak in cold water for 24 hours
Sow in spring
Helleborus 16ºC-18ºC (61ºF-64ºF) up to 1 year Sow in autumn
Fresher seed will germinate best.
Needs period of cold moist stratification
Hesperis 18ºC-21ºC (64ºF-70ºF) up to 30 days Sow in spring
Sow 3mm deep
Heuchera 16ºC-21ºC (61ºF-70ºF) up to 90 days Leave seeds uncovered when sown, as requires light to germinate
Chilling may improve germination
Germination can be erratic
Hibiscus 18ºC-21ºC (64ºF-70ºF) up to 90 days Soak seed for several hours in hot water before sowing
Sow 1-2mm deep
Germination can be erratic
Hosta 10ºC-16ºC (50ºF-61ºF) more than 90 days Lightly cover seeds
Hyacinthoides 10ºC-16ºC (50ºF-61ºF) up to 1 year Sow in autumn, lightly covering seeds
Requires a period of cold moist stratification
Hydrangea 13ºC-16ºC (55ºF-61ºF) more than 90 days Surface sow seed in spring
Indigofera 16ºC-21ºC (61ºF-70ºF) 30-90 days Soak seed in warm water for 24 hours before sowing
Sow 5mm deep
Germination can be erratic
Ipomoea 18ºC-24ºC (64ºF-75ºF) up to 90 days Pre-soak in cold water for a few hours and chipping seed will help with germination
Use well drained compost
Iris 13ºC-18ºC (55ºF-64ºF) up to 1 year Requires a period of cold moist stratification
Kalmia 16ºC-21ºC (61ºF-70ºF) 30 days Sow in spring and leave seeds uncovered when sown
Keep compost moist and retain high humidity 
Kolkwitzia 10ºC-13ºC (50ºF-55ºF) 30-90 days Chilling may improve germination
Kniphofia 16ºC-21ºC (61ºF-70ºF) up to 60 days Surface sow in spring as light is needed for germination
Lavandula 13ºC-18ºC (55ºF-64ºF) up to 90 days Lightly cover seeds
Requires a period of cold moist stratification
Lepechinia 18ºC-24ºC (64ºF-75ºF) up to 90 days Leave seeds uncovered when sown
Use well drained compost
Libertia 10ºC-13ºC (50ºF-55ºF) may take more than 1 year Species resents root disturbance - sow directly into suitable container
Requires a period of cold moist stratification
Lilium 18ºC-21ºC (64ºF-70ºF) may take more than 1 year Surface sow and cover pot with lime-free grit. Best sown in summer as needs warm stratification for 4 weeks, followed by a period of cold moist stratification
Liriodendron 10ºC-16ºC (50ºF-61ºF) more than 90 days Requires a period of cold moist stratification
Lobelia 18ºC-24ºC (64ºF-75ºF) up to 90 days Leave seeds uncovered when sown
Requires light to germinate
Lunaria 16ºC-21ºC (61ºF-70ºF) up to 90 days Sow in summer, covering seeds with 3mm compost. Germination may be slow and erratic and seeds may need a period of cold, moist stratification
Lupinus 13ºC-18ºC (55ºF-64ºF) up to 90 days Soak seeds in hot water for 1-3 days before sowing. Alternatively chip seed
Sow seeds 5mm deep
Luzula 18ºC-21ºC (64ºF-70ºF) up to 30 days Sow in spring
Lightly cover seeds
Germination may be slow and irregular and seeds may need a period of cold, moist stratification
Lychnis 16ºC-21ºC (61ºF-70ºF) up to 30 days Leave seeds uncovered when sown
Requires light to germinate
Lysimachia 13ºC-18ºC (55ºF-64ºF) up to 90 days Leave seeds uncovered when sown
Chilling may improve germination
Germination can be erratic
Lythrum 18ºC-21ºC (64ºF-70ºF) up to 30 days Lightly cover seeds
Matthiola 16ºC-21ºC (61ºF-70ºF) up to 30 days Sow 2mm deep, but do not exclude light
Miscanthus 21ºC-27ºC (70ºF-81ºF) up to 90 days Surface sow in spring as light is needed for germination. If germination does not occur then cold moist stratification may be required for 2-4 weeks
Molinia 10ºC-16ºC (50ºF-61ºF) may take up to 6 months Sow in autumn, lightly covering seeds
Needs a period of cold moist stratification
Myrrhis 18ºC-21ºC (64ºF-70ºF) may take up to 6 months Sow in autumn
Needs a period of cold moist stratification
Germination may be slow and erratic
Nepeta 16ºC-21ºC (61ºF-70ºF) up to 90 days Lightly cover seeds
Nicandra 16ºC-24ºC (61ºF-75ºF) 30-90 days Lightly cover seeds
Nicotiana 21ºC-24ºC (70ºF-75ºF) up to 90 days Leave seeds uncovered when sown
Requires light to germinate
Nigella 13ºC-18ºC (55ºF-64ºF) up to 90 days Lightly cover seeds
Can be sown direct outside
Orlaya 16ºC-21ºC (61ºF-70ºF) 30-90 days Lightly cover seeds. If germination is poor then cold stratify for 6-8 weeks
Panicum 16ºC-21ºC (61ºF-70ºF) may take up to 6 months Sow in spring, lightly covering seeds
Papaver 13ºC-18ºC (55ºF-64ºF) up to 90 days Best sown direct 
Very lightly cover seeds
Pennisetum 18ºC-21ºC (64ºF-70ºF) up to 30 days Sow in spring in well draining compost
Persicaria 10ºC-16ºC (50ºF-61ºF) up to 90 days Sow in autumn, lightly covering seeds
Needs a period of cold moist stratification
Phacelia 10ºC-16ºC (50ºF-61ºF) up to 30 days Suitable for sowing direct outside between March and September
Seed need darkness to germinate 
Phlomis 16ºC-18ºC (61ºF-64ºF) up to 90 days Lightly cover seeds
Phytolacca 16ºC-21ºC (61ºF-70ºF) may take up to 6 months Sow in autumn
Needs a period of cold moist stratification
Platycodon 18ºC-21ºC (64ºF-70ºF) 30-90 days Leave seeds uncovered when sown
Requires light to germinate
Potentilla 18ºC-21ºC (64ºF-70ºF) 30-90 days Lightly cover seeds
Primula 13ºC-16ºC (55ºF-61ºF) up to 90 days Leave seeds uncovered when sown
Requires a period of cold moist stratification
Pulsatilla 13ºC-16ºC (55ºF-61ºF) up to 1 year Lightly cover seeds
Requires a period of cold moist stratification
Rodgersia 13ºC-16ºC (55ºF-61ºF) more than 90 days Sow in spring
Leave seeds uncovered when sown as needs light to germinate
Chilling may improve germination
Rudbeckia 16ºC-18ºC (61ºF-64ºF) up to 30 days Lightly cover seeds. If germination is poor then cold stratify for 4 weeks
Salvia 18ºC-24ºC (64ºF-75ºF) up to 30 days Sow in spring and leave seeds uncovered when sown
Use well drained compost
Scabiosa 16ºC-21ºC (61ºF-70ºF) up to 90 days Sow in spring
Sow 2mm deep
Germination can be erratic
Silene 16ºC-21ºC (61ºF-70ºF) up to 30 days Lightly cover seeds
Sisyrinchium 13ºC-18ºC (55ºF-64ºF) up to 1 year Lightly cover seeds
Germination can be slow and erratic
Spartium 13ºC-18ºC (55ºF-64ºF) up to 90 days Sow in spring, soaking seed in warm water for 12 hours before sowing. Sow 6mm deep.
Stachys 18ºC-21ºC (64ºF-70ºF) 30-90 days Sow in spring
Lightly cover seeds
Stipa 18ºC-21ºC (64ºF-70ºF) 30-90 days Use well drained compost
Succisa 18ºC-21ºC (64ºF-70ºF) up to 90 days Lightly cover seeds
Germination can be slow and erratic
Tellima 10ºC-16ºC (50ºF-61ºF) more than 90 days Lightly cover seeds
Teucrium 16ºC-21ºC (61ºF-70ºF) up to 30 days Sow in spring
Lightly cover seeds
Thalictrum 13ºC-18ºC (55ºF-64ºF) up to 30 days Lightly cover seeds
Tigridia 21ºC-27ºC (70ºF-81ºF) up to 1 year Species resents root disturbance - sow directly into suitable container
Trifolium 18ºC-21ºC (64ºF-70ºF) 30 days Sow in spring, lightly covering seeds
Trollius 10ºC-16ºC (50ºF-61ºF) may take more than 1 year Sow in spring
Leave seeds uncovered when sown
Cold stratify for 3 weeks. Chilling may improve germination
Keep moist
Umbilicus 16ºC-21ºC (61ºF-70ºF) up to 90 days Leave seeds uncovered when sown
Cold stratify for 2 weeks
Use well drained compost
Verbascum 15ºC-18ºC (59ºF-64ºF) up to 30 days Lightly cover seeds
Verbena 18ºC-21ºC (64ºF-70ºF) up to 90 days Lightly cover seeds
Germination may be slow and erratic
Veronica 13ºC-18ºC (55ºF-64ºF) up to 90 days Leave seeds uncovered when sown
Requires light to germinate
Veronicastrum 16ºC-21ºC (61ºF-70ºF) up to 90 days Leave seeds uncovered when sown
Requires light to germinate
Viburnum 18ºC-21ºC (64ºF-70ºF) may take more than 1 year Warm stratify for 4 weeks; Cold stratify for 4 weeks
Chilling may improve germination
Watsonia 10ºC-16ºC (50ºF-61ºF) may take more than 1 year Sow seeds 3mm deep
Species resents root disturbance

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