Store your dahlia tubers in a cool, dry place until the risk of frost has past, usually by April/May when you can plant your tubers outside in a sunny position with well-drained soil.
Alternatively, you can start your dahlia tubers off in March/April in pots and grow them on indoors in a frost-free location like a greenhouse before transferring them outside after the last frosts.
If planting in the garden, cover your tubers with 3cm (1-2") of soil. Allow approx. 30cm spacing between each tuber. (The spacing may vary depending on the final size of the variety.)
If planting in pots, plant 1 x dahlia tuber in a 2 to 3 litre pot or 12" in diameter and fill with multi-purpose compost. Use a slow-release fertiliser to promote strong growth.
If planting in the garden, mulch over to protect them from the risk of any frost, douse the hole with a watering can full of water and cane as you plant.