When to plant French Marigolds in London

Sow seeds into modules around 18th February - 14th March in a fine seed compost, covering them with 0.5 cm of compost. Keep them at 18–20 °C and just moist, then prick out the seedlings once they are large enough to handle.

Move seedlings on when roots fill the module, keeping them growing steadily before planting out. Handle them by the leaves, not the stems, and keep them in bright light so they do not get leggy.

Acclimatise plants over 7 to 10 days before planting out, giving them short spells outdoors in a sheltered spot. Keep them protected from cold nights and hard rain until they are ready for the border or container.

Plant out around 18th April - 2nd May into a sunny, free-draining position, spacing plants 20 cm apart. Water in thoroughly straight away and keep young plants protected from late cold snaps.

From 18th May onwards, remove faded flowers regularly so the plant keeps producing new blooms instead of setting seed. Water during dry spells and keep checking through 10th November for the best display right up to the autumn frosts.