When to plant Cosmos in Manchester

Sow seeds in trays or modules from 3rd March to 27th March, using 0.5 cm of fine compost. Keep them at 18–21 °C and just moist, not wet.

Move seedlings on when they are large enough to handle, from 17th March to 24th April. Pot them into small pots and keep them growing in a bright, frost-free place.

Acclimatise plants over 15 days before planting out, from 17th April to 1st May. Put them outside in the daytime at first, then leave them out for longer each day so they do not check in cold weather.

Plant into free-draining soil from 1st May to 18th May, spacing plants 30 cm apart. Water in thoroughly straight after planting and protect young plants from slugs and late cold snaps if needed.

Remove fading flowers regularly from 31st May to 8th November. This stops the plant setting seed too early and keeps it producing flowers until the autumn frosts. Tie in taller stems if the plants get blown about, and water during dry spells.