Gradually expose potted dahlias to lower temperatures before planting out in April
Move dahlias outside during the day towards the end of this month to acclimatise them to lower temperatures and harden off ready for planting out. It takes two or three weeks before they are ready.
Start by bringing them in at night and providing the temperatures don’t plummet, after a week, leave them out somewhere sheltered. The extra air movement around them dries out the tubers easily, so water them in the morning to keep them in growth.