Cotton thistle (Onopordum acanthium)

Cold germination: sow outdoors at the beginning of spring or in autumn. Alternatively you can use artificial stratification, as follows. Mix the seeds with moist sand in a plastic bag. Keep the bag warm and moist (approx. +20°C) for the first 2-4 weeks and then place it in the refrigerator and keep it at a temperature of +5°C for 5-6 weeks. Then remove the plastic bag from the refrigerator and remove the seed and sand mix from the bag. Keep the sand mix at room temperature and check the seeds regularly to see when they germinate. Prick the seedlings into pots and plant them out after the last frosts in mid-May.