The best time to plant daffodil bulbs in the UK is in early autumn, ideally September through November. Planting in this period allows the bulbs time to develop strong roots before the winter frost. They should be planted at a depth of about 10-15 cm and spaced about 10 cm apart in well-drained soil with good sunlight or partial shade. Planting can be done as late as December or even January with some extra care, but earlier planting gives better results. For indoor forced daffodil bulbs, planting can start in September for flowering around Christmas or New Year. Overall, autumn planting is optimal for a bright spring bloom from about March to May depending on the variety.