Althaea Seed - rosea nigra Ref: TM01408935 SowingSow on the surface of the compost in late winter in John Innes Compost. Make sure that the compost is moist but not wet and seal in a polythene bag until after germination which usually takes 12-21 days at 15-21C (65-70F). Do not exclude light which is beneficial to germination.<p>They can also be sown in mid summer, overwintered in a coldframe and planted out in spring. This produces larger plants.GrowingTransplant when large enough to handle into 8cm (3in) pots and grow on in cooler conditions. Gradually acclimatise to outdoor conditions for 10-15 days before planting out after all risk of frost 38cm (15in) apart in well cultivated garden soil and some shelter.Aftercare FloweringSummercroppingPlant typeHardy Herbaceous Perennial Price: £2.49 Quantity: