When to plant Zinnias in London

In a warm, sheltered garden with light, free-draining soil, sow seeds where they are to flower around 9th May - 23rd May, to a depth of 1 cm. Water gently and keep the seedbed just moist until seedlings appear.

Check the seedbed around 9th May - 6th June and water at soil level whenever the surface begins to dry. Avoid wetting the leaves, as damp foliage encourages fungal disease.

Thin seedlings around 23rd May - 13th June once they are easy to handle, leaving the strongest plants 30 cm apart. Remove weaker seedlings carefully so the remaining roots are not disturbed.

Around 13th June - 11th July, pinch out the main growing tip above a pair of leaves when plants are 20–30 cm tall to encourage branching. Support tall cultivars with canes or netting before the stems become top-heavy.

Every 14 days from 1st August to 10th November, cut flowers for the house or remove fading blooms back to a leaf joint. Regular cutting and deadheading encourage the plants to keep producing flowers until frost.