When should I sow Florence fennel in the UK?

Late April to mid-July direct outdoors. Don't sow earlier — cold weather triggers bolting later. Successional sowings every 3 weeks until early July give continuous picking from July to October. Late-July sowings of bolt-resistant cultivars can crop into November in mild south-coast gardens.

Why does my Florence fennel bolt before forming a bulb?

Three usual causes. Cold check after sowing triggers the plant to think it's been through a winter; the response is to bolt. Sow into warm soil only (above 12°C). Drought stress triggers bolting as a survival response. Bolt-prone cultivar — older varieties (Zefa Fino) bolt readily in UK conditions; choose bolt-resistant modern cultivars (Romanesco, Mantovano, Finale).

What's the difference between Florence fennel and herb fennel?

Same species (Foeniculum vulgare), different cultivar groups. Florence fennel (var. azoricum): grown for the swollen leaf-base bulb; annual; eaten as a vegetable. Herb fennel (var. dulce or wild form): grown for the feathery foliage and aromatic seeds; perennial; reaches 2 m+; ornamental as well as edible. Both produce identical-tasting foliage and seeds; only the bulb-forming form gives the fleshy white root vegetable.

Can I grow Florence fennel in containers?

Yes — a 25 cm deep container grows 4–6 plants. Use rich peat-free compost; water consistently (containers dry out fast); thin to one per station. Container plants need watering daily in summer to avoid the drought-bolting trap.

When are Florence fennel bulbs ready to harvest?

When they're fist-sized — 8–12 cm across at the widest point. Check the bed weekly once swelling starts; the window from perfect to starting to bolt is short, often just a week or two. Cut at ground level with a sharp knife. Smaller young bulbs are more tender for salads; larger ones suit roasting and braising.

Can I eat the feathery green foliage?

Yes — the fronds above the bulb are edible and intensely aniseed-flavoured. Pick lightly through the growing season; chop into salads, mix into mayonnaise for fish, sprinkle over roasted vegetables. The flowers and seeds (if you let the plant bolt) are also edible. The whole plant is essentially the same as herb fennel; the bulb is just the extra prize.

Knollenfenchel

Foeniculum vulgare var. azoricum

Sow Florence fennel seed direct from April to July; bulbs swell in cool moist weather and bolt in heat or cold check, so timing matters more than for most crops. Florence fennel is half-hardy (RHS H3–H4) and the bulb-forming form distinct from herb fennel (same species, different cultivar group, same slug needs to be disambiguated — herb fennel under separate slug `fennel-herb`). Plant 30 cm apart in rich moist soil; thin from clusters; earth up the developing bulb to keep it tender and white. Pick bulbs when they're fist-sized (8–12 cm across) — checking weekly once they start to swell. The classic UK bolting risk: cool dip after planting, hot summer, or simply growing the wrong cultivar — Romanesco and Mantovano are the most bolt-resistant.

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