Growing and harvesting dahlias

01Planting

1. 1.Wait until soil has warmed and frost danger has passed — typically around or after your last frost date.
2. 2.Choose full sun and well-drained soil; dahlias rot in cold, wet ground.
3. 3.Dig a hole about 4–6 in (10–15 cm) deep and lay the tuber flat with the eye (growing point, near the old stem) facing up.
4. 4.Space plants about 18–24 in (45–60 cm) apart; large-flowered types need the wider spacing.
5. 5.Put the stake in at planting time so you don't spear the tuber later.
6. 6.Cover with soil and don't water again until shoots appear, unless the soil is very dry.

02Growing

• —When the plant is about 12 in (30 cm) tall, pinch out the central tip above the third or fourth set of leaves for a bushier plant with more stems.
• —Tie stems to the stake as they grow, or use horizontal netting.
• —Water deeply once or twice a week in dry weather.
• —Watch for slugs and snails on young shoots, and for earwigs and aphids in summer.

03Harvesting

• —Cut when the flower is almost fully open. Dahlias do not continue opening much after cutting.
• —Cut deep, just above a leaf pair, for long stems and more buds.
• —Place stems in a few inches of hot (not boiling) water for about an hour, then arrange. Expect roughly 4–6 days in the vase.
• —Regular cutting and deadheading keep plants flowering until frost.

04Winter

Regional noteDahlias survive the ground over winter only in mild climates (often cited as USDA zone 8 and warmer, with good drainage and mulch). In colder areas, lift and store tubers.

1. 1.After the first frost blackens the foliage, cut stems down to about 4–6 in (10–15 cm).
2. 2.Lift the clumps carefully with a fork, shake off soil, and let them dry for a day under cover.
3. 3.Label each clump. Store in crates in slightly damp wood shavings, peat or vermiculite, somewhere cool and frost-free, around 40–50 °F (4–10 °C).
4. 4.Check monthly; remove any rotting tubers and lightly mist if they shrivel.