How do you prepare fennel for winter?
Written by
Julia Anderson
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Fennel preparation for winter needs to be different depending on your climate and plant. Bulbing types must be harvested before frost, whereas perennials can survive if protected. I have overwintered fennel for five seasons, and I have learned successful methods through trial and error. How you prepare will impact next year's growth.
Bulbing Fennel
- Timing: Harvest bulbs when temperatures drop below 32°F (0°C)
- Technique: Cut at soil line leaving 2 inches (5 cm) of stem attached
- Storage: Keep in cool dark place at 34-38°F (1-3°C) for 2 weeks maximum
Perennial Leaf Fennel
- Pruning: Cut back foliage to 6 inches (15 cm) after first hard frost
- Mulching: Apply 8-inch (20 cm) straw layer covering root zone completely
- Protection: Add burlap windbreak in zones below 5 for extra insulation
Container Plants
- Transition: Move indoors before temperatures reach 45°F (7°C)
- Location: Place near south-facing windows with supplemental grow lights
- Care: Reduce watering to once weekly and stop fertilizing completely
Consider using a layer of mulch strategically for perennial fennel's eventual survival. Straw will work best as leaves compact and rot. Form mounds of 8 in (20 cm) around pruned perennial fennel plants extending 12 in (30 cm) beyond the drip line. Create an upright mound with chicken wire to prevent it from blowing away. Remove it over time when the temperature is above 40°F (4°C).
Get container plants ready for moving indoors. Gradually acclimate for 7 days to reduce sunlight. Thoroughly inspect for pests and treat with neem oil if necessary. Use well-draining pots that have saucers to protect floors. Maintain humidity with pebble trays and avoid wetting leaves.
Do your late fall harvest for bulbs before the ground freezes. Pick firm bulbs with a diameter of 3-4 inches (7.5-10 cm) and cut them cleanly. Cure in a dry, dark location for two days. Store in perforated bags at near-freezing temperatures, checking for soft spots weekly.
Keep an eye on overwintered plants in thaw periods. If temperatures rise to above 50°F (10°C) for more than three days, temporarily remove mulch. Reapply mulch when it is cold. This is to avoid unwanted growth that could be easily damaged by frost. Your careful management will provide plants with vigorous re-growth in spring.
Read the full article: How to Grow Fennel Successfully at Home
