Florence Fennel Companion Planting

Fennel (Foeniculum vulgare) root exudates contain trans-anethole and other volatile compounds with demonstrated allelopathic effects. These compounds inhibit seed germination and seedling growth of many vegetable crops including tomato.

Grow fennel isolated from all vegetable beds. Best in its own container or a separate garden section.

Fennel allelopathic compounds (primarily trans-anethole and fenchone) suppress germination and reduce fruit set in Capsicum species. Root zone overlap amplifies the effect.

Keep fennel at least 4 feet from pepper plants. Part of the broad fennel allelopathy pattern.

Fennel allelopathic compounds (trans-anethole, fenchone) inhibit carrot germination and root development. Additionally, fennel and carrot are both Apiaceae and can cross-pollinate if both flower, degrading seed quality.

Separate widely. If saving seed from either, ensure isolation distances of at least 500 meters.

Fennel root exudates containing trans-anethole and related monoterpenes suppress bean seed germination and inhibit early seedling growth through allelopathic interference.

Fennel is antagonistic to nearly all vegetables. Grow in isolation.

Fennel allelopathic compounds inhibit growth of Solanaceae family members including ground cherry. Same allelopathic mechanism as fennel-tomato.

Keep fennel isolated from all Solanaceae family members.