Sow in 7.5cm (3") pots, 0.5cm (½") deep in March-May in a propagator at 20-25°C (68-77°F), or a clear plastic bag on a sunny windowsill. Once germinated (14-28 days), take the lid off, or remove the bag. Can be direct sown in May-June, into weed-free, warm soil. Do not over water, or water foliage as plants can suffer from botrytis if too wet. Final spacing should be 30cm (12"). Zinnia hate root disturbance, so if growing in pots, be very careful when planting out.