Companion Plant Guide
Tomato
Inhibits tomato growth.
Herb · Umbellifer family
Fennel companion plants
Foeniculum vulgare
What to plant beside fennel, what to keep apart, and how to grow it — sun, spacing, soil and the pairings used in this guide.
Photo: Luca Volpe on Unsplash
Overview
Growing fennel beside the right neighbour
Fennel (Foeniculum vulgare) is a herb in the Umbellifer family. Tall herb that inhibits many plants but attracts beneficial insects.
Fennel is the one crop to plant on its own — almost nothing thrives beside it.
Give plants 12–18 in in full sun. Aim for well-draining, moderate fertility. In most gardens the crop sits in USDA zones 3-10 and is ready in about 90-150 days.
Grows well with
What to plant with fennel
This guide does not yet list crops that grow especially well beside fennel. Use the growing notes and keep-apart list until more pairings are recorded.
Keep apart
What not to plant with fennel
Keep fennel away from Tomato, Basil, and Bean. These neighbours compete for the same food, release chemicals that stunt growth, or otherwise hold the crop back.
Basil
Inhibits basil growth and germination.
Bean
Inhibits bean growth.
In the bed
How to grow fennel
| Sun | Full sun |
|---|---|
| Spacing | 12–18 in |
| Soil | Well-draining, moderate fertility |
| Hardiness | Zones 3-10 |
| Days to maturity | 90-150 |
These notes sit beside the companion lists — they are how fennel actually occupies the bed, not a substitute for local climate.
- Plant away from most vegetables
- Attracts beneficial insects
- Self-seeds readily
- Use seeds and foliage for cooking
Questions
Fennel companion planting FAQ
What can I plant next to fennel?
This guide does not yet list good companions for fennel.
What should I not plant with fennel?
Keep fennel apart from Tomato, Basil, and Bean. Tomato: Inhibits tomato growth. Basil: Inhibits basil growth and germination. Bean: Inhibits bean growth.
How much sun does fennel need?
Fennel wants full sun. Space plants 12–18 in apart in well-draining, moderate fertility.
How long does fennel take to mature?
Most fennel crops in this guide mature in 90-150 days, in hardiness zones 3-10.
Compare every pairing at a glance
Open the guide, pick fennel, and see what thrives alongside it — and what quietly holds it back.
Open the pairing guide