GardenFennel variety
Romanesco Fennel
✓ In your garden
Romanesco is a florence bulbing fennel, ready in about 90 days. The calendar below has your zone’s planting dates, and the fennel page has the full growing basics.
Growing basics — shared by every fennel
Romanesco grows like any other fennel. The full picture — how deep to plant, spacing, feeding, pests, harvest — lives on the Fennel page so it's maintained in one place.
- Sun
- Full Sun
- Spacing (in row)
- 8–12 in
- Row spacing
- 18 in
- Planting depth
- 0.25–0.5 in
- Soil pH
- 6.5–8
- Water
- Moderate
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Want the full 10/50/90% odds + nearest stations? Open the frost tool →When to plant Romanesco in your zone
Zone 6bGreenhouse or cover on: your start slides ~4 weeks earlier and your harvest stretches ~3 weeks later (shown striped).
Planting seeds straight in the ground only works where the season's long and warm — most gardeners start seeds indoors or buy young plants, or you'd pick your first tomato right as frost hits.
Comfortable — first ripe fruit lands around mid Jul, well before your typical frost (~late Oct).
- Start seeds indoors
- early Mar – mid Mar
- Plant seeds outside
- mid Apr – early May
- Growing
- early May – mid Jul
- Picking
- mid Jul – late Jul
Typical dates for zone 6b — set your zone or ZIP above for yours.
What to plant near Romanesco — and what to keep away
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TomatoPractical
Fennel foliage and seed are rich in trans-anethole, and extracts of them held back germination and seedling growth across a range of species in testing. Whole-plant effects at garden spacing are milder than the "fennel kills everything" reputation, but the chemistry is real — give it its own pot.
The badge is the honesty. Trialed = a published field trial · Practical = a real mechanism · Traditional = companion-chart lore. These pairings hold for every fennel.
Pairings compiled from El-Kenany & El-Darier.
Romanesco fennel at a glance
| Type | Florence Bulbing |
|---|---|
| Days to ripe | 90 days after you plant it outside |
Extra fields from seed-catalog listings and university growing guides. Days to ripe and disease resistance shift with your climate and seed source — double-check with your local extension office before you buy.
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Common questions about Romanesco
How long does Romanesco take to grow?
About 90 days. See the fennel page for your zone’s planting dates.
Browse more fennel varieties →