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SuNutri
Fennel
Beginner

Fennel

Foeniculum vulgare

Family: Apiaceae

Fennel is a tall, feathery perennial herb with an unmistakable licorice-anise flavor used throughout Mediterranean and Asian cuisines. All parts of the plant are edible—the aromatic fronds season dishes like dill, the seeds are a prized spice, and the pollen is a gourmet delicacy. This is herb fennel (leaf type), distinct from bulbing Florence fennel.

Days to Harvest

90-115 days

Sun Needs

Full Sun (6-8+ hours)

Water Needs

moderate

Germination Temp

70°F optimal

Seed Starting

Start Indoors

4 weeks before last frost

Germination

7-14 days

Seed Depth

1/4 inch

Light to Germinate

No

💡 Tip: Fennel has a taproot and dislikes transplanting. Direct sowing is preferred. If starting indoors, use deep pots and transplant carefully while young. Seeds germinate readily without special treatment.

Growing Conditions

Soil Type

Well-draining, average to rich soil. Tolerates poor soil.

pH Range

6 - 8

Spacing

12-18 inches between plants for good air circulation

Companion Plants
BrassicasLettuceCucumbersAromatic herbs

⚠️ Avoid planting near:

Dill (cross-pollinates)Coriander (cross-pollinates)TomatoesBeans
History & Nutrition

History

Foeniculum vulgare (fennel) has been cultivated for over 4,000 years, with evidence of its use found in ancient Egypt, China, and around the Mediterranean. The ancient Egyptians used fennel as a food, medicine, and ceremonial herb, while the Greek name "marathon" derives from the Battle of Marathon (490 BCE), fought on a field of fennel—the Greek word "marathos" means fennel, and the town took its name from the abundant wild fennel growing there. The Romans were passionate about fennel, using it to treat over 22 different ailments and believing it improved eyesight and gave courage—gladiators mixed fennel into their food before entering the arena. Pliny the Elder wrote that serpents ate fennel when shedding their skin to restore their sight, reinforcing the association with eye health. During the Middle Ages, fennel became one of the nine sacred herbs of the Anglo-Saxons, hung over doors on Midsummer's Eve to ward off evil spirits and protect against witchcraft. Medieval monks cultivated fennel in monastery gardens for medicinal use, and chewing fennel seeds became customary during long church services to suppress hunger and mask bad breath. Charlemagne's famous "Capitulare de villis" of 812 CE mandated fennel cultivation on all imperial farms. Italian immigrants brought fennel to North America, where it naturalized widely in California, becoming so abundant along roadsides that it's now considered invasive in some regions. The phrase "to sell fennel" in ancient Greece meant to deceive or flatter, possibly because fennel was used to bulk up inferior products. Today, fennel is essential to Mediterranean, Middle Eastern, Indian, and Chinese cuisines, prized for its sweet anise flavor in everything from Italian sausage to French bouillabaisse to Indian panch phoron spice blend. Wild fennel grows prolifically in California, where chefs forage the pollen as a premium ingredient.

Nutritional Benefits

  • Rich in fiber for digestive health
  • High in Vitamin C and antioxidants
  • Good source of potassium and manganese
Climate & Temperature

Optimal Growing Temp

60°F - 75°F

Fennel prefers moderate temperatures. Grows best in cool weather but tolerates heat. Bolts in hot weather.

Survival Range

40°F - 90°F

Can survive these temperatures

semi hardy
cool Season

Frost Note: Tolerates light frosts but killed by hard freezes. Perennial in zones 6-10, annual elsewhere.

Best USDA Zones

Zone 6Zone 7Zone 8Zone 9Zone 10

Humidity

40-60%

Tolerates a range. Good air circulation helps prevent disease.

Plant Size & Growth

Height

3-5 feet

Spread

18-24 inches

Growth Habit

upright

perennialRoot Depth: Deep taproot (12-18 inches). Difficult to transplant once established.
Growth Stages

Germination

10-14 days

Direct sow preferred due to taproot. Seeds germinate easily.

Seedling Stage

Duration: 4-6 weeks

True leaves: Feathery, dill-like leaves emerge with anise scent.

Transplant ready: If starting indoors, transplant when 3-4 inches tall. Handle taproot carefully.

Vegetative Growth

Duration: 60-90 days

Tall, feathery foliage develops. Harvest fronds continuously. Forms bulb in bulbing varieties.

Flowering

Timing: 90-120 days (triggered by heat/day length)

Duration: 3-4 weeks

Umbrella flower heads attract beneficial insects. Produces edible seeds.

Harvest Maturity

Timing: 60-90 days for fronds; 90-120 for seeds

  • Full height reached
  • Ready to flower
  • Seeds turning brown
Expected Yield

Per Plant

Abundant fronds all season; 2-4 tablespoons seeds per plant.

Per Square Foot

1 plant per 1-2 square feet (needs space)

Harvest Frequency

Harvest fronds continuously. Seeds once per season after flowering.

Factors Affecting Yield

  • Cool weather delays bolting
  • Regular frond harvest
  • Full sun
Watering Guide

Seedling Stage

Keep consistently moist.

Established Plants

Water when top inch dry. Every 3-4 days.

During Fruiting

Moderate water during flowering and seed development.

Preferred Method

Water at soil level. Consistent moisture prevents bolting.

Pro Tips

  • Consistent moisture delays bolting
  • Mulch to retain moisture
Fertilizing Guide
moderate feederRecommended: Balanced 10-10-10

Feeding Schedule

Planting

Compost

Once

Growing

Liquid fertilizer

Every 3-4 weeks

Organic Options

CompostFish emulsionWorm castings

Regular feeding supports continuous frond production.

Container Growing
✓ Suitable for containers

Minimum Size

12 inch pot

Recommended Size

14-18 inch pot

Depth Required

At least 14-18 inches for taproot

Best Varieties for Containers

Bronze fennelHerb fennel (not bulbing types)

Container Tips

  • Deep container essential for taproot
  • Herb fennel works better in containers than bulbing types
  • May need staking when tall
  • Keep moist but well-drained
Succession Planting

Plant Every

Every 3-4 weeks

Sowings/Season

2-3 plantings

Duration

Spring through early summer; again late summer

Tips

  • Succession plant for continuous frond harvest
  • Later plantings provide seed harvest
Frequently Asked Questions

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