When to plant Zinnias in Edinburgh

Sow seeds in modules around 27th April - 11th May, about 1 cm deep in fine compost. Keep them warm and bright, and water lightly so the compost stays just moist.

Pot seedlings on around 11th May - 1st June, as soon as they have their first pair of true leaves. Move them into individual small pots so the roots do not become cramped, and keep them warm in good light without overwatering.

Harden plants off over 15 days before planting out, from 25th May to 8th June. Put them outside during the day at first, then bring them in at night until they cope with cooler air and brighter sun.

Plant out around 8th June - 22nd June into fertile, free-draining soil in a warm, sunny, sheltered position, spacing plants 30 cm apart. Water in thoroughly straight away, and protect young plants from slugs.

From 8th June to 16th October, water at soil level during dry spells and avoid wetting the leaves, as damp foliage encourages fungal disease. Once flowering begins, feed plants in containers with a high-potash liquid feed according to the label.

Around 22nd June - 20th 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 20th July to 16th October, 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.