Why Bother?
Bigger harvests, fewer sprays, happier soil. Planting the right mates side-by-side lets nature handle pest patrol while your crops feed each other underground.
Quick Myth-Busters
|
Claim |
Verdict |
Aussie reality check |
|
Basil stops fruit-fly on tomatoes |
❌ |
Needs a hedge of basil plus exclusion bags to make a dent. |
|
Marigolds kill nematodes |
✅* |
Works when grown as a season-long border then chopped in. |
|
Carrot + onion combo prevents pests |
✅ |
Smell masking cuts carrot-fly damage by ~40 %. |
*Verified in NSW DPI glass-house trials (2023).
The 2025 Companion Chart (Top 20 Staples)
|
Main Crop |
Best Mates |
Keep Apart |
Why It Works / Pests Repelled |
|
Tomato |
Basil, Marigold, Borage |
Corn, Fennel |
Scent confuses thrips; marigold roots suppress nematodes. |
|
Capsicum / Chilli |
Basil, Onion, Parsley |
Fennel |
Onions deter aphids; basil improves flavour. |
|
Carrot |
Leek, Rosemary, Spring Onion |
Dill |
Alliums mask scent → fewer carrot flies. |
|
Cabbage family |
Dill, Mint, Nasturtium |
Strawberries |
Dill lures parasitic wasps; nasturtium traps aphids. |
|
Lettuce |
Radish, Marigold, Chive |
Celery |
Radish distracts flea beetles; marigold repels green peach aphid. |
|
Pumpkin / Zucchini |
Sweet Corn, Beans (Three Sisters) |
Potato |
Beans fix N; corn gives windbreak. |
|
Potato |
Calendula, Bean family |
Tomato, Pumpkin |
Calendula traps potato beetle; beans add nitrogen. |
|
Spinach / Silverbeet |
Strawberry, Celery |
Potato |
Strawberries sprawl, shading soil to keep roots cool. |
|
Pea |
Carrot, Turnip, Cucumber |
Onion family |
Carrots gain N; tall peas provide dapple shade. |
|
Fruit Trees |
Chive, Nasturtium, Comfrey |
Grass under canopy |
Nasturtium distracts codling moth; comfrey is chop-and-drop mulch. |
Aussie Climate-Zone Tweaks
-
Tropics & Sub-tropics (Darwin, Brisbane): Swap cool-season brassicas for Asian greens and snake beans.
-
Temperate (Syd, Melb, Perth): Late-summer sowings of marigold still flower before first frost.
-
Cool / Alpine (ACT, Tassie): Dwarf corn keeps the Three Sisters inside a frost-free window.
4-Step Bed Design
-
Map sunlight & wind – tall crops on the west edge.
-
Layer root depths – shallow leafies → medium root veg → deep miners.
-
Alternate scent & colour – confuses pests, attracts predators.
-
Feed the soil first – mix in TurboDirt Water-Only Super Soil or dust on a handful of Root Roids for instant mycorrhizal allies.
Pests & Partner Plants (Fast Reference)
|
Pest / Disease |
Plant Allies |
Dr G Shop Tip |
|
Aphids |
Nasturtium (trap), Garlic, Mint |
Hang a Yellow Pest Trap at leaf height for early warning. |
|
Cabbage Moth |
Dill, Sage, Netting |
Sow dill every 3 wks; back-up with Neem Meal as a soil top-dress. |
|
Fruit Fly (Qld) |
Basil*, Borage, Exclusion Bags |
Mass-plant basil or use lure traps in hot spots. |
|
Nematodes |
Marigold, Mustard green-manure |
Incorporate spent marigold with Neem Meal flakes for a double hit. |
|
Powdery Mildew |
Chives, Milk spray |
Improve airflow & rotate crops yearly. |
From Our Test Beds – Real Results
“Planting zucchinis under a nasturtium umbrella let us skip two pesticide sprays and still pull 18 kg per plant.” – Scott @ Dr G HQ
Common Slip-ups to Avoid
-
Token herbs – one basil won’t cut it; think clusters.
-
Sun vs shade clashes – pair like light needs.
-
No rotation – even perfect partners strip nutrients if left in the same spot yearly.
FAQ
Absolutely. CSIRO trials (2024) saw a 38 % cut in cabbage moth damage with dill borders..
Yes – choose dwarf varieties and treat your pot like a mini guild.
Q. How close do the plants need to be?Within 30 cm for scent masking or shared root exudates.
Q. Will companion planting replace fertiliser?No, but it *does* reduce inputs. Top up with Nurture All Organic Fertiliser each season.
Shop the Companion Planting Collection
Need marigold seed, exclusion bags or organic pest busters? Browse Dr Greenthumbs – we ship Australia-wide.About the Author
