When to plant Petunias in the UK

Sow seeds thinly into modules or trays around late February to late March on the surface of fine compost. Do not cover them, as light aids germination. Keep them warm and bright, then prick out the seedlings once they are large enough to handle.

Move young plants into small pots when roots fill the modules, usually from late March. Grow them on in bright, frost-free conditions so they do not become drawn.

From early May, acclimatise the plants gradually by putting them out during the day and bringing them in at night. Keep them sheltered from cold winds and cover with fleece if a cold snap is forecast.

Plant into beds, borders, or containers from mid-May, once all risk of frost has passed and the soil has warmed a little. Space plants 25 cm apart, water them in thoroughly straight away, and keep fleece handy if nights turn cold.

From mid-May, tuck petunias into gaps between vegetables such as tomatoes to attract pollinators and fill space. Choose a sunny spot and water the roots in well after planting.

Remove fading flowers from mid-June onwards to stop the plant setting seed and to keep it producing more blooms. Check plants every few days, water containers before they dry out, and keep going until late October when the first frosts finish the display.