Fennel
Fennel is a herb in the Apiaceae family. It grows best in full sun with medium moisture, and is listed for USDA zones 4-9. Plants reach harvest about 64–115 days after planting and sit about 12 inches apart.
Varieties
7 from High Mowing, Seeds Now & True Leaf Market · sorted by days to maturity▸Preludio F164–86 days
Bolt resistant; 4” bulbs
Very early, heavy bulbs with superb flavor—a major improvement in hybrid fennel. This variety stood out in our trials with its lightly sweet flavor, uniformity and ability to hold in the field without bolting. Upright plants are easy to harvest. Early variety recommended for spring and summer harvest with good fall performance as well. From Vitalis Organic Seeds.
Growing notes: Days to maturity are from transplants. Fennel is a hardy annual. Cool weather, fertilization and irrigation produce the largest and sweetest bulbs. Direct seed fennel mid-spring through late summer or start transplants 4-5 weeks before planting date. Plant outdoors after danger of hard frost has passed. Bolting can result from disturbing the roots. Remove all seed stalks to preserve quality. Harvest bulbs at 3-4” in diameter. Greens will hold quality for a week and bulbs will store for many months; remove stalks and wrap bulbs separately in plastic. Store in cooler as close to freezing as possible.
View on High Mowing ↗▸Solaris F164–86 days
Uniform baby bulbs; 3-4” bulbs
Our earliest fennel with excellent bulbing. Stout, heavy bulbs grow to an impressive size crowned by feathery foliage. Juicy texture without woodiness or dryness; pleasant anise flavor. A standout variety for all seasonal slots and an excellent choice for baby fennel. Our growers in the Pacific Northwest say Solaris F1 holds better than other varieties for later season sales. Originally from our partners at Bejo Seeds.
Growing notes: Days to maturity are from transplants. Fennel is a hardy annual. Cool weather, fertilization and irrigation produce the largest and sweetest bulbs. Direct seed fennel mid-spring through late summer or start transplants 4-5 weeks before planting date. Plant outdoors after danger of hard frost has passed. Bolting can result from disturbing the roots. Remove all seed stalks to preserve quality. Harvest bulbs at 3-4” in diameter. Greens will hold quality for a week and bulbs will store for many months; remove stalks and wrap bulbs separately in plastic. Store in cooler as close to freezing as possible.
View on High Mowing ↗▸Dragon F168–92 days
Exceptional uniformity; Bolt resistant; 3-4" bulbs
Large, elongated bright white bulbs with sweet, aromatic, juicy flesh, exceptional flavor and upright growth. Bulbs are dense, long and gorgeous with beautiful dark green fronds. Excellent field holding quality of fronds, color and bulb texture. From our partners at Bejo Seeds.
Growing notes: Days to maturity are from transplants. Fennel is a hardy annual. Cool weather, fertilization and irrigation produce the largest and sweetest bulbs. Direct seed fennel mid-spring through late summer or start transplants 4-5 weeks before planting date. Plant outdoors after danger of hard frost has passed. Bolting can result from disturbing the roots. Remove all seed stalks to preserve quality. Harvest bulbs at 3-4” in diameter. Greens will hold quality for a week and bulbs will store for many months; remove stalks and wrap bulbs separately in plastic. Store in cooler as close to freezing as possible.
View on High Mowing ↗▸Finale68–92 days
Bolt resistant; 4” bulbs
Vigorous plants were a hit in our trials, producing huge juicy bulbs. Very large, uniform bulbs with slightly flattened shape. Finale stores well, keeping good quality and maintaining a crisp, juicy texture and pleasant flavor. Excellent bolt resistance. Unavailable in 2024
Growing notes: Days to maturity are from transplants. Fennel is a hardy annual. Cool weather, fertilization and irrigation produce the largest and sweetest bulbs. Direct seed fennel mid-spring through late summer or start transplants 4-5 weeks before planting date. Plant outdoors after danger of hard frost has passed. Bolting can result from disturbing the roots. Remove all seed stalks to preserve quality. Harvest bulbs at 3-4” in diameter. Greens will hold quality for a week and bulbs will store for many months; remove stalks and wrap bulbs separately in plastic. Store in cooler as close to freezing as possible.
View on High Mowing ↗▸Florence68–92 days
Can tolerate hot temperatures; Direct sow; Grows well in full sun; Grows well with containers; Grows well with raised beds; Matures in <90 days; Start indoors; Super easy to grow
Produces very flavorful large bulbs and edible flower buds - Excellent for seasonings and for cooking as a vegetable - Plant Height: 30" tall - Fennel is a very aromatic plant with a sweet licorice flavor, similar to an anise seed. It has many medicinal uses and herbalists have been using it for centuries to relieve problems with the respiratory system, stomach muscles and intestines. Nursing mothers can expect increased milk production and fennel also has been used to soothe colicky infants. - Fennel has a long history of herbal use and is a commonly used household remedy, being useful in the treatment of a variety of complaints, especially those of the digestive system. - Easy to grow - There are so many health benefits associated with this plant Days to Maturity | 80 days Fennel Seeds | Fennel is known as a perennial that ought to be planted sometime after the last frost of the winter. Try sowing seeds directly into your gardens, because transplanting fennel usually doesn't work very well. Click here for complete Fennel grow guide See Fennel Recipes & Growing Tips on our Pinterest Board Follow SeedsNow.com's board Fennel on Pinterest.
View on Seeds Now ↗▸Orion F170–94 days
Bolt resistant; 3-4” bulbs
Large, uniform, rounded bulbs with high yield potential. Heavy bulbs that hold well in the field with good tolerance to tip burn and bolting. An extremely reliable producer across a variety of conditions with strong late season vigor for baby bulbs in the fall. The team at The Crow's Farm harvesting the fennel bounty in Burlington, Washington.
Growing notes: Days to maturity are from transplants. Fennel is a hardy annual. Cool weather, fertilization and irrigation produce the largest and sweetest bulbs. Direct seed fennel mid-spring through late summer or start transplants 4-5 weeks before planting date. Plant outdoors after danger of hard frost has passed. Bolting can result from disturbing the roots. Remove all seed stalks to preserve quality. Harvest bulbs at 3-4” in diameter. Greens will hold quality for a week and bulbs will store for many months; remove stalks and wrap bulbs separately in plastic. Store in cooler as close to freezing as possible.
View on High Mowing ↗▸Sweet90–115 days
Heirloom; Non-GMO; Container; Vegetable
90-115 days to maturity. Sweet Fennel (Foeniculum vulgare var. azoricum), also called Florence fennel, is grown for its crisp, white, celery-like bulbous bases and feathery green fronds, which carry a sweet, licorice-like flavor. The swollen bulb is eaten raw in salads, braised, or roasted, and is widely used in Italian cuisine, while the fronds and seeds serve as a herb and seasoning. Suitable for garden plots, raised beds, and containers.
View on True Leaf Market ↗
Plant spacing
In a square-foot bed, space fennel about 12 in apart — that fits 1 plant in each 1-foot square (1×1). Wider rows or containers space the same.
Plan your fennel planting
Add fennel to a free GardenDraft plan and get sow, transplant, and harvest dates computed for your ZIP code — with a drag-and-drop bed layout and reminders when it’s time to plant.
Start your free plan →At a glance
Storing & preserving
Best used right away — quality drops fast. Refrigerate stems in water, or wrap in a damp towel for a few days.
- Dry: Dehydrate or air-dry, then store airtight away from light.
- Freeze: Freeze chopped in oil or water in ice-cube trays.
General home-preservation guidance — for tested processing times and safety, follow the National Center for Home Food Preservation.
Growing timeline
Companion planting — with cited sources
From US/Canada cooperative-extension publications and peer-reviewed studies. Evidence-tier dots show how strongly each recommendation is backed: ●●● peer-reviewed mechanism · ●● extension consensus · ● traditional knowledge with a plausible mechanism.
Avoid planting near (5)
- CarrotEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative, alternate-host-pest
Fennel root and shoot exudates (anethole, fenchone, estragole) are documented to inhibit germination and seedling growth of multiple vegetables including carrot, tomato, bean, and lettuce. The crop is also a shared Apiaceae pest host. US/Canada extension references consistently flag fennel as a poor neighbor and recommend isolating it in its own bed.
Source: S4, University of Maryland Extension
- Common BeanEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Fennel exudates suppress bean germination and early growth in documented assays. Extension recommendation: keep fennel in an isolated bed.
Source: University of Maryland Extension
- Common TomatoEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Same fennel allelopathy applies to tomato: lab and field reports of fennel suppressing tomato seedling growth.
Source: University of Maryland Extension
- DillEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationalternate-host-pest
Fennel and dill cross-pollinate and share Apiaceae pests; extension home-garden references advise not planting them together. Also degrades seed-saving purity for both.
Source: University of Maryland Extension
- Sweet Bell PepperEvidence tier C: Traditional practice with plausible mechanism but limited empirical replicationallelopathy-negative
Fennel (Foeniculum vulgare) releases allelochemicals (anethole and related compounds) reported to inhibit growth of multiple vegetables, with peppers among the commonly cited sensitive crops in extension companion-planting summaries.
Source: S7
Sources cited
- S4
- Oregon State University Extension Service
- S7
- University of Minnesota Extension
- S9
- University of Maryland Extension — Home & Garden Info Center
Care & troubleshooting— extension-sourced, with citations
When to feed, prune & water
Attract beneficial insects and protect pollinators
Protection- Routine carePlant insectary flowers and tolerate light pestsstrong evidence — extension confidence
Grow a diversity of flowering plants (including small-flowered umbels and asters) to feed predators and parasitoids, and tolerate low pest numbers so natural enemies have prey to stick around.
- Routine careNever spray open bloomsstrong evidence — extension confidence
Avoid insecticides on flowering plants and apply any needed sprays in the evening when pollinators aren't active, and favor selective products over broad-spectrum ones to spare bees and beneficials.
Mulch to suppress weeds and retain moisture
Mulch- Routine careApply organic mulch around plantsstrong evidence — extension confidence
Spread a few inches of straw, shredded leaves, or compost around established plants (keeping it off stems) to hold soil moisture, suppress weeds, and moderate soil temperature; wait until soil has warmed for heat-loving crops.
Plan crop rotation
Rotation- Routine careRotate plant families between bedsstrong evidence — extension confidence
Avoid planting the same family in the same bed in consecutive years (aim for a 3+ year gap), grouping crops by family so soilborne diseases and pests that build up don't carry over to the next susceptible crop.
- Routine careSequence for soil healthmoderate evidence — extension confidence
Follow heavy feeders like tomatoes and brassicas with legumes or a cover crop to support soil fertility and structure, and keep simple notes each year so you can track where each family grew.
Thin crowded seedlings to final spacing
Thinning- Routine careThin to ~2 in spacing, then again later· every 3 wks · ~3 wksstrong evidence — extension confidence
Crowded carrots stay small and forked. Thin to about 1 in when seedlings are 2-3 in tall, then to 2-3 in a few weeks later. Snip rather than pull to avoid disturbing neighbors.
Clean up debris and sanitize at season end
SanitationUnusual this time of year.
- Routine careRemove spent plants and fallen debrisstrong evidence — extension confidence
Pull and clear old plants, dropped fruit, and leaf litter at season end, since many pests and diseases overwinter in this debris; dispose of diseased material rather than composting it.
- Routine careClean tools, stakes, and cagesmoderate evidence — extension confidence
Wash and sanitize stakes, cages, and tools that touched diseased plants before storing or reusing them to avoid carrying pathogens into next season.
Something looks wrong?
Describe what you see on your fenneland we'll rank the likely causes — most likely first, least-invasive fix first.
Bacterial soft rot
Diseasesevere- CulturalRemove rotting plants and produce (manage, not cure)strong evidence — extension confidence
Soft rot can't be cured once tissue breaks down; promptly remove and discard affected plants and produce so the bacteria don't spread to neighbors or other stored vegetables.
- CulturalAvoid wounds and excess moisturestrong evidence — extension confidence
Harvest in dry conditions, handle gently to avoid bruising, control insects that create entry wounds, and improve drainage; cure and store bulbs and roots cool and dry.
- CulturalDon't overwater and rotatemoderate evidence — extension confidence
Avoid waterlogged soil and overhead watering that splashes bacteria, and rotate away from previously affected fleshy crops to lower disease pressure.
Southern blight
Diseasesevere- CulturalRemove infected plants and surrounding soil (manage, not cure)strong evidence — extension confidence
Once a plant collapses it can't be cured; dig out the plant plus the top few inches of nearby soil containing sclerotia and dispose of it, avoiding spread on tools.
- CulturalBury residue and rotatemoderate evidence — extension confidence
Deep-turn soil to bury sclerotia, remove crop debris at season end, and rotate susceptible solanaceous and legume crops with grasses for several seasons.
- CulturalAdjust soil pH and plant earlymoderate evidence — extension confidence
Maintain soil pH at the level recommended for the crop, since the disease is worse in low-pH soils, and time plantings so harvest begins before peak summer heat favors the fungus.
White mold (Sclerotinia stem rot)
Diseasesevere- CulturalRemove infected plants (manage, not cure)strong evidence — extension confidence
There's no cure for an infected plant; cut out and bag affected plants including the black sclerotia, and don't compost them, since sclerotia survive years in soil.
- CulturalOpen the canopy and rotatestrong evidence — extension confidence
Space plants widely, control weeds, orient rows to prevailing wind, and avoid overhead watering at bloom to dry the canopy; rotate to non-host crops (corn or other grasses) for several years.
- CulturalWater at the base, not overheadmoderate evidence — extension confidence
Use drip or soaker irrigation to keep foliage and the soil surface drier, which discourages the sclerotia germination and mycelial growth that drive white mold.
Carrot rust fly
Pestmoderate- CulturalRow cover + delay sowingstrong evidence — extension confidence
Cover the bed with insect netting from sowing, and avoid the spring egg-laying peak by sowing a little later. Crop rotation helps.
Root rot from overwatering / poor drainage
Diseasemoderate- CulturalLet soil drain and water lessstrong evidence — extension confidence
Water root rots like Pythium thrive in saturated soil, so cut back watering, let the surface dry between irrigations, and water at the base rather than keeping soil constantly wet.
- CulturalImprove drainage and aerationstrong evidence — extension confidence
Use raised beds, loosen compacted soil, and add organic matter to improve drainage; remove plants that are already rotted since affected roots won't recover.
Tarnished plant bug / lygus
Pestmoderate- CulturalManage surrounding weedsstrong evidence — extension confidence
Keep broadleaf weeds mowed or removed around the garden, since lygus build up on flowering weeds and move to crops as those weeds dry down; avoid mowing large weedy areas right beside fruiting crops at bloom.
- CulturalVacuum or shake plants to monitor and reduce· every 5 daysmoderate evidence — extension confidence
Tap plants over a light-colored tray to check for nymphs; a handheld vacuum used once or twice weekly can hold low to moderate numbers down on small plantings.
- OrganicTreat nymphs if damage is building· every 1 wkmoderate evidence — extension confidence
For active nymph infestations, azadirachtin or a Beauveria bassiana product can give some control per the label; preserve the parasitic wasps and other natural enemies that help suppress lygus.
Aphids
Pestlow- CulturalBlast off with water· every 3 days · ~2 wksstrong evidence — extension confidence
Knock colonies off with a strong jet of water in the morning; repeat every few days. Light infestations rarely need more.
- OrganicInsecticidal soap - label use only· every 1 wk · ~3 wksmoderate evidence — extension confidence
For persistent colonies apply insecticidal soap to undersides per label. Avoid open flowers.