Dahlias need a sunny situation sheltered from strong winds, in a well drained soil enriched with well-broken-down compost, blood and bone, and a balanced general fertiliser such as Nitrophoska Blue. They prefer to have an area devoted entirely to them, rather than to be mixed with other plants. However, they will perform quite well in a mixed planting if given adequate feeding and watering.
It is suggested Tubers be planted at the end of October (Labour weekend is ideal). Any shoots longer than 25mm should be cut back to the first node. Smaller flowering cultivars may be planted 60 – 75cm apart, others approximately 1m apart as adequate ventilation between the plants is very important. Stakes (1.5 – 1.8m) should be placed in the ground before planting to avoid damage to the tuber. Place the tuber on its side, 25mm from the stake and 120-160mm deep. Water well and continue to keep watered and fed throughout the growing season. Mulching is advisable where possible.
Tie the plant to the stake at around 20cm high and again as necessary as growth dictates. Pinching out the top shoots will lead to bushier, sturdier plants. Disbudding will produce better flowers with longer stems for picking. Dead-head the flowers frequently to keep new buds forming. Spray for earwigs and caterpillars with a suitable insecticide, if necessary.
Pick flowers in the cool early morning or evening and scald the stems in 20mm of boiling water for 1 minute before placing in a deep container of cold water.