Introduction
Bulb fennel is a cool-season plant that is grown as an annual crop and considered native to the Mediterranean region. Sicily, Italy, is the primary bulb fennel production region in Europe.The average temperature in Sicily during bulb fennel seeding (November–December) is 55 °F, and during harvest (March–May) it is 63 °F (Weatherbase, 2017). This is similar to the growing climate of Mount Vernon, WA, during the spring (52 °F) and summer (61 °F) production seasons (Washington State University, 2019). The high market value of bulb fennel is also supported by its significant health benefits.
Bulb Fennel Production 
This slide show includes temperature requirements, cultivar, planting design, and harvest of bulb fennel.
- Bulb Fennel Production (slide show).
Research Report
This bulb fennel cultivars that are suitable for production in the Northwest United States.
- Bulb Fennel Variety Trials (pdf).