When to plant China Asters in London

Sow seeds in trays or modules around 18th February - 14th March in a light seed compost. Cover with a shallow layer of compost and keep at 18–21 °C until they germinate. Keep the compost just moist, not wet.

When seedlings are large enough to handle, prick them out from 4th March into small pots. Handle them by the leaves and keep them growing on in bright light so they do not go leggy.

Start hardening off from 21st March and give them around 10 days to adjust. Put plants outside during the day at first, then leave them out for longer so they settle before planting.

Plant out from 18th April into fertile, well-drained soil once all frost risk has passed. Space plants 30 cm apart, water in thoroughly straight after planting, and keep them sheltered from strong wind.

Start deadheading from 18th May and keep going until 10th November. Remove fading flowers regularly so the plant does not set seed, which keeps it producing more blooms right through to the autumn frosts. Keep the soil evenly moist in dry spells and pinch out any weak or floppy growth.