Petunias in Barnton

Sow seeds thinly into modules or trays around 14th January - 24th March on the surface of fine compost and barely cover them with 1 cm. 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 3rd March. Grow them on in bright, frost-free conditions so they do not become drawn.

From 31st March, acclimatise the plants outdoors over 7 to 10 days 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 14th April, 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.

Set petunias among suitable vegetables from 28th April to help fill gaps and bring in pollinators. They work well near tomatoes, and a mixed planting is easiest if the roots are watered in well and the plants are given enough light.

Remove fading flowers from 28th May 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 6th October when the first frosts finish the display.