Companion Planting Principles: The Complete Walkthrough

This guide covers companion planting principles, rated an easy task, typically taking planning only.

This is the expanded version of our companion planting principles guide, for anyone who wants the full detail rather than just the quick-reference card.

Plan the bed as a community

Companion planting groups plants that support each other — repelling pests, attracting beneficial insects, improving flavour, or making efficient use of space — rather than growing everything in isolated blocks.

Before You Start

Worth paying attention to:

• A garden plan or notebook
• Knowledge of which plants pair well (see individual crop guides for specifics)
• A mixed range of vegetables, herbs, and flowers to work with

Step by Step

Keep these points in mind:

• 1. Start with your main crops, then identify known companions for each (check individual grow guides).
• 2. Interplant beneficial pairings — e.g. basil near tomatoes, marigold as a general pest deterrent.
• 3. Avoid known antagonistic pairings (e.g. alliums near legumes).
• 4. Include flowers and herbs specifically to attract pollinators and beneficial insects, not just edible yield.
• 5. Observe and adjust each season — companion planting benefits are real but often subtle, and local conditions vary.

When Things Go Wrong

Worth paying attention to:

• No obvious benefit observed — companion planting effects are often modest and cumulative rather than dramatic; don't expect a single pairing to solve a serious pest problem.
• Overcrowding — interplanting still needs to respect each plant's actual space and light requirements.
• Conflicting information between sources — much companion planting advice is traditional/anecdotal rather than rigorously tested; treat it as a reasonable starting heuristic, not an absolute rule.
• Difficulty planning a diverse bed — start simple, with 2–3 well-documented pairings, rather than trying to optimise everything at once.

Keeping It Going

Best time — at the planning stage, before each planting — ideally sketched out ahead of the season. Duration — an ongoing practice reconsidered each planting cycle rather than a one-off task. Maintenance — review and adjust the plan each season based on what worked and what didn't. Signs of success — a generally more resilient, diverse bed with fewer severe pest outbreaks than a monoculture block.

For the condensed printable version, head to the main guide page linked below.

→ View the printable A4 guide for companion planting principles