Helianthus annuus For Cutting Collection Seeds Ref: TM01402969 SowingSow indoors in February/March individually 12mm (½in) deep in 7.5cm (3in) pots of good seed compost. Germination takes 1-2 weeks at 20C (70F).<p>They can also be sown outdoors, in moist well raked soil, where they are to flower in March/April when the soil has warmed. Sow the seeds 15cm (6in) apart, 12mm (½in) deep, in rows 12in (30cm) apart. Keep the soil moist until the seedlings are growing well. When large enough to handle, thin out the seedlings to 12in (30cm) apart.GrowingGrow cool and well lit. Gradually acclimatise to outdoor conditions for 10-15 days before planting out 30cm (12in) apart after all risk of frost has gone.Aftercare They prefer a sunny open site but will grow in most soils.FloweringSummercroppingPlant typeHardy Annual Price: £3.31 Quantity: