🌿 Fennel

Foeniculum vulgare
herbs Perennial herb (often grown as annual/biennial)
Illustration of Fennel
☀️ Sun
Full sun; 6+ hours daily.
💧 Water
Consistent moisture; drought-tolerant once established.
🗺️ Zones
USDA zones 4-9 as perennial; elsewhere as annual
🪴 Soil Type
Well-draining, rich soil; pH 6.0-7.0. Tolerates poor soil.
🧪 Soil pH
5.5-7.0 (prefers well-drained, fertile soil)
📏 Spacing
18-24 inches apart (isolated bed recommended)
📐 Height
36-72 inches (can reach 8 feet)
📅 Days to Maturity
60-90 days for leaves; 100-120 days for seeds

🍴 Edible Parts

🍽️ ["Bulb (Florence fennel)"🍽️ "Leaves (fronds)"🍽️ "Seeds"🍽️ "Pollen"🍽️ "Stems"]

🤝 Companions (1)

🤝 None — plant in isolated area
Fennel is strongly allelopathic — it secretes substances that inhibit growth of most neighboring plants. It is the #1 herb you should NOT interplant. Some sources suggest it may be fine with dill in a separate bed, but this is risky.

⚠️ Keep Apart (51)

⚠️ Almost everything
Fennel releases allelopathic chemicals from roots and leaves that inhibit seed germination and growth of beans, tomatoes, peppers, kohlrabi, caraway, coriander, and virtually all garden vegetables.
⚠️ Coriander/Cilantro
Fennel severely inhibits cilantro growth; also cross-pollinates, ruining both seed crops.
Cross-pollination risk; fennel suppresses dill growth.
⚠️ Beans
Strong growth inhibition; beans are particularly sensitive to fennel's allelopathy.
⚠️ Tomatoes
Stunted growth and poor fruit set reported.
Mutual antagonism; both herbs suffer.
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of artichoke. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of arugula. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of ashwagandha. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of asparagus. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of beet. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of bell pepper. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of bok choy. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of borage. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of brussels sprouts. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of bush bean. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of carrot. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of celery. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of cilantro. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of collard greens. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of cucumber. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of edamame. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of eggplant. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of endive. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of fava bean. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of jalapeño pepper. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of kohlrabi. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of leek. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of lettuce. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of melon. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of mustard greens. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of nasturtium. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of okra. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of parsnip. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of pole bean. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of pumpkin. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of radish. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of runner bean. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of rutabaga. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of spinach. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of strawberry. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of summer squash. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of sweet corn. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of sweet potato. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of swiss chard. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of tomato. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of turnip. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of watermelon. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of winged beans. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of winter squash. Keep well separated (30+ ft).
Fennel is strongly allelopathic — its root exudates inhibit germination and growth of zucchini. Keep well separated (30+ ft).

💊 Medicinal Uses

{"conditions_treated": ["Infant colic and gas (traditional gripe water ingredient \u2014 anethole is carminative)", "Adult digestive issues (bloating, gas, IBS, indigestion, heartburn)", "Breastfeeding issues (galactagogue \u2014 increases milk production)", "Menstrual cramps and irregular cycles (phytoestrogenic; emmenagogue)", "Menopausal symptoms (phytoestrogenic activity)", "Respiratory congestion (expectorant \u2014 loosens phlegm)", "Conjunctivitis and eye irritation (fennel tea eyewash \u2014 traditional)", "Bad breath (chewed seeds; antimicrobial)"], "preparation_methods": ["Fennel seed tea: 1-2 tsp crushed seeds steeped 10 min; for digestive issues, colic, breastfeeding support", "Eye compress: Cooled fennel tea applied to closed eyes for conjunctivitis and eye strain", "Tincture: 1:5 in 45% alcohol; 2-4ml 3x daily for digestive issues", "Chewing seeds: Chew 1 tsp after meals for digestion and breath freshening (common in Indian restaurants)", "Fennel honey: Seeds infused in honey for cough \u2014 especially for children", "Essential oil: Diluted for abdominal massage (colic, menstrual cramps)"], "active_compounds": ["Anethole", "Fenchone", "Estragole", "Flavonoids", "Coumarins"], "toxicity_warnings": "Generally very safe in culinary amounts. Avoid medicinal doses during pregnancy (estragole and phytoestrogenic effects). May interact with hormone therapies and birth control pills. Estragole is a potential carcinogen in very high isolated doses \u2014 not a concern with normal use. Pure essential oil should not be ingested. Not for long-term high-dose medicinal use."}

📜 History & Traditional Uses

{"medieval": "Hung over doorways on Midsummer's Eve to ward off evil spirits. Used as a 'slimming' herb \u2014 thought to suppress appetite (hence use during Lent). Key ingredient in medieval 'gripe water.' Used in love potions.", "ancient": "Ancient Greek 'marathon' \u2014 the Battle of Marathon was fought in a field of fennel. Pythagoras and Hippocrates recommended fennel. Romans used it extensively \u2014 Pliny listed 22 remedies using fennel. Used by Roman soldiers as a general tonic during long marches.", "folk_medicine": "One of the most universal digestive remedies across European, Middle Eastern, Indian, and Chinese medicine. 'Anise' and fennel have interchangeable folk uses. Used as 'nurse's tea' in Europe for breastfeeding women. In Ayurveda, fennel is a sattvic food that calms all three doshas."}