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Plant library  ·  Vegetables

Fennel (Bulb)

Foeniculum vulgare var. azoricum

Bulb fennel is a compact annual vegetable grown for its crisp, anise-flavored base. Reaching about 2 feet tall and 1 foot wide, it brings a vertical, feathery texture to a sunny food garden without taking over the bed. Allow it to occupy its space through the growing season, then clear the planting area after the late-summer to early-fall harvest.

Sunlight Full Sun
Water Regular
Planning spacing 1 ft
Typical mature size 2 ft tall, 1 ft wide
Typical harvest Late summer - early fall

Fennel (Bulb) spacing and mature footprint

Space Fennel 12 inches apart, measured center to center (30 cm).

The mature spread is about 12 inches (30 cm), so neighboring plants just meet at maturity without crowding.

Treat 12 inches as a planning baseline — cultivar and local growing conditions shift the final footprint.

Compare with the full vegetable spacing chart

Three plants set 1 ft apart, center to center; shaded circles show the 1 ft mature spread.

Placement and use

Set bulb fennel in a full-sun bed where regular watering is easy to provide, such as alongside a path, hose line, or drip zone. Its upright form works well behind low crops, but keep the base accessible for watering, weeding, and harvest. Give it its own short row or a defined section of the vegetable bed rather than tucking it among tomatoes, beans, cabbage, kale, coriander, or dill.

Spacing and mature footprint

Plant bulb fennel 1 foot apart, center to center. That spacing matches its roughly 1-foot mature spread, creating a continuous row while leaving enough definition around each developing base. In a rectangular bed, reserve a 1-foot-wide strip per row and provide path-side access so plants can be reached without stepping into the planting area.

Sun, water, and soil

Choose a sunny, sheltered position with loose, fertile soil that holds moisture but drains freely. Keep the root zone evenly moist from establishment through bulb formation; dry spells can interrupt growth and trigger early flowering instead of a well-formed harvest. A mulch layer can help the bed retain moisture and reduce competition from weeds.[1]

Seasonal notes

This is a 90-day crop, with harvest expected from late summer into early fall. Plan its bed as a seasonal opening: it can follow an earlier crop, then make way for a fall planting after harvest. Keep the planting accessible through its full run, since the crop needs steady attention rather than occasional watering.

Planning caveats

Bolting is the main planning risk. Cold conditions, disturbed roots, dry soil, and heat stress can send plants into flower before the bases enlarge, so avoid sites that are difficult to water or prone to abrupt moisture swings. Where spring weather is unsettled, a later warm-season sowing can reduce that risk.[1]

Growing facts

Botanical name
Foeniculum vulgare var. azoricum
Type
Vegetable
Category
Vegetables
Lifecycle
annual
Sunlight
Full Sun
Water
Regular
Planning spacing
1 ft
Typical mature size
2 ft tall, 1 ft wide
Typical days to maturity
About 90
Typical harvest season
Late summer - early fall
Plan a garden with fennel

References

  1. How to grow Florence Fennel — RHS