When should I sow sunflower seeds in the UK?

Late April to early May direct outdoors in southern England; mid-March to mid-April indoors in modules for transplanting. Don't sow direct outside before mid-April — cold wet soil rots the seeds. A sheltered sunny spot is essential; sunflowers in the shade are leggy and stunted.

How tall do sunflowers grow?

Varies hugely by cultivar. Dwarf (Teddy Bear, Sunspot, Pacino): 45–60 cm — ideal for containers and small gardens. Medium (Velvet Queen, Italian White, Vanilla Ice): 1.5–2 m — most flower beds. Tall (Russian Giant, Mongolian Giant, Titan): 3–4 m — back of a border with staking. Multi-headed (Soraya, Lemon Queen): 1.5–2 m with many smaller heads on one plant for cut flowers.

How do I stop slugs eating sunflower seedlings?

The first 4 weeks after emergence are the danger zone. Apply nematodes (Phasmarhabditis hermaphrodita) to warm moist soil before sowing. Beer traps near the bed. Hand-pick at dusk in damp weather. Copper rings on bare soil around each seedling. Once stems are 30 cm tall and starting to lignify, slug pressure drops sharply.

Why is my sunflower not following the sun?

Mature flower heads don't track the sun — only young growth does (a phenomenon called heliotropism, driven by uneven cell elongation on the shaded side). Once the bud opens, the flower fixes facing east (where it warms first in the morning), and stays there. Mature sunflower fields all face the same direction. Nothing wrong with your plant.

When should I cut sunflowers for vases?

Just as the petals open and the back of the head is still green. Earlier than this and they don't fully open; later, they're too far gone for a long vase life. Cut in the cool of the morning, plunge straight into water, recut underwater before arranging. Sunflowers last 5–7 days in clean water (change daily).

Can I save sunflower seeds for next year?

Yes — let one or two heads mature fully on the plant. When the back of the head turns brown and dry and the seeds are plump and loose, cut the whole head and hang upside down in an airy dry place for 2 weeks to fully dry. Rub or pick seeds out, store in a paper envelope in a cool dry place. F1 hybrids don't come true from saved seed; open-pollinated varieties (Russian Giant, Mammoth Russian) do.

Girasole

Helianthus annuus

Sow sunflower seed direct from late April outdoors or in modules indoors from March. Sunflowers are frost-tender annuals (RHS H1c) and want a sunny sheltered spot in any decent garden soil. Tall varieties (Russian Giant, Mongolian Giant) reach 3–4 m and need staking; medium types (Velvet Queen, Italian White) reach 1.5–2 m and stand on their own; dwarf varieties (Teddy Bear, Sunspot) reach 45–60 cm and suit containers. Plant 30–60 cm apart depending on type. Slugs strip seedlings — protect for the first 4 weeks. Pick stems for cut flowers when the petals have just opened and the back of the head is still green. Leave seed heads on tall plants in autumn for the birds.

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