Companion Planting Chart for Australian Vegetables

Updated October 2026

What to plant with tomatoes, brassicas, beans and more, which flowers feed the helpful insects in your climate, and an honest look at what works

Companion planting is the practice of growing certain plants near each other so they help one another, and keeping apart the ones that do not get along. Done well, it draws in helpful insects, confuses pests, makes better use of space, and can lift the health of a whole bed. Done as blind superstition, it does very little. This guide gives you a printable chart for 53 crops, a picker that explains the reason behind each pairing for 29 of them, partners for tomatoes, brassicas, cucurbits and corn with sow windows for all ten regions, the flowers that feed beneficial insects in each climate, and a clear-eyed account of what the evidence supports.

What companion planting can and cannot do

Companion planting works when one plant changes something physical or biological for its neighbour. It casts shade, feeds an insect that eats pests, passes on a little nitrogen, or sits closer to a pest than the crop does. It is oversold when it claims that a plant repels pests across a whole bed or changes the flavour of a tomato. The table sorts the common claims by how much evidence sits behind them, strongest first.

What it cannot do

• Fix the soil. Compost, mulch and drainage do more for a bed than any pairing. Feed the soil first and let the companions finish the job.
• Replace crop rotation. Fusarium wilt, verticillium wilt, white rot and clubroot live in the soil for years, and a neighbouring herb does not remove them. The rotation section below shows how the two fit together.
• Replace watching your plants. Predators help, but a bad run of aphids or caterpillars still needs you to notice and act. Our Pest & Disease Guide starts every fix with the mildest option.
• Stop weather-driven disease. Blight, powdery mildew and downy mildew follow humidity and leaf wetness, so airflow, spacing and dry leaves matter more than who is next door.
• Rescue the wrong plant in the wrong spot. A sun-lover in shade or a tender crop planted out into frost will struggle whatever grows beside it.

The keep apart lists in the chart include two kinds of pair. Some share a pest or disease, as tomato and potato both do with blight, and those are worth taking seriously. Others are traditional pairings where the harm is reported but has not been tested well. For those, choose a different spot when you have the room, and do not worry if a small bed leaves you no choice.

What pairs with...

Pick a crop below to see its best companions, the ones to keep apart, and the reason for each. Every pairing here is a widely accepted one, and where a benefit is traditional rather than proven we have kept the claim modest.

Quick-reference chart: the classic pairings

A short version for the most popular crops, using the classic garden pairings. The full chart at the top of the page is built from our plant data, and the picker above gives the reason behind each pairing.

Classic combinations explained

The Three Sisters: corn, beans and squash

The most famous companion system of all, developed by Indigenous farmers across the Americas. The corn grows tall and gives the climbing beans a living pole. The beans fix nitrogen in the soil, feeding the heavy-feeding corn. The squash sprawls across the ground, its big leaves shading out weeds and keeping the soil cool and moist. Three crops sharing one patch, each doing a job for the others. It is reliable because every part of it rests on a real mechanism.

Tomato, basil and marigold

A kitchen-garden classic. Basil grows happily alongside tomatoes and the pair ends up on the same plate, so it is convenient as well as traditional. Both basil flowers and marigold draw in pollinators and predatory insects, and French marigolds grown as a block can reduce root-knot nematodes in the soil. The flavour-boosting claim is folklore, but the insect and soil benefits are real enough to make this a worthwhile trio.

Carrots and onions

An old pairing built on pest confusion. The smell of onions is thought to mask carrots from the carrot fly, and the smell of carrots to muddle the onion fly. The evidence is mixed, but the two interleave neatly, use the bed efficiently, and do each other no harm, so it remains a sensible combination.

Lettuce under taller crops

Pure use of space and light. Lettuce and other leafy greens bolt and turn bitter in fierce summer sun. Tucked into the shade of staked tomatoes, climbing beans or sweet corn, they stay tender and cropping for longer while making use of ground that would otherwise sit bare. This one is simple, practical and works every time.

Planting partners for the big crops

Four crops account for most companion questions: tomatoes, brassicas, cucurbits and the corn, bean and squash trio. Each block below names the partners and the neighbours to avoid, says what the planting actually does, and gives the sow window for each region from our regional calendar, so the partners go in when the crop does. Click a region to see its full calendar.

Tomatoes, capsicum, chilli and eggplant

Plant with: basil, parsley, chives, carrot, garlic, borage, marigold and nasturtium, with lettuce at the foot of staked plants. Capsicum, chilli and eggplant share most of that list, and capsicum also likes okra and oregano. Keep apart: potato, brassicas, fennel, rosemary and sweet corn.

Low herbs and lettuce use the shade and bare soil under staked tomatoes. Alyssum and marigold flowers feed the hoverflies and lacewings that eat the aphids and whitefly tomatoes attract. Marigold protects against nematodes only as a dense pre-crop, as the evidence table above explains. Tomato and potato are the pair to separate firmly, because both catch early and late blight. Rotate them so neither returns to a bed within three years, and read our blight guide before the season starts. Keep companion herbs low and trimmed back from the lower leaves, because blight and other leaf diseases spread in damp, crowded foliage.

Tomato timing varies more by region than any other crop here, and the companions need to be ready when the tomatoes go out. The table shows the sow window for each region.

• Melbourne: tomato and basil open in October, with marigold and nasturtium open from September. Plant the whole bed together from mid October in the inner suburbs and from Cup Day for most suburbs, once the soil passes 16°C. Hills gardens wait until late November.
• Hobart and Canberra: the tomato window opens first, September to October in Tasmania and October to November in Canberra, and basil does not open until November in both. Set tomatoes out after the last frost (early October in Hobart, early November in Canberra) and add basil about a month later in Hobart and in the same week in Canberra.
• Sydney, Perth and Adelaide: tomatoes are started indoors in July and August and planted out from September in Sydney, mid September on the Perth plain and mid October in Adelaide. Basil and marigold windows open in August or September, so seedlings of both go out alongside the tomatoes.
• South East Queensland and Northern Rivers: there are two tomato windows, February to April and again in August to September (September only on the Northern Rivers). Marigold and nasturtium, open March to October, cover both. In hinterland frost pockets on the Northern Rivers, wait until mid September.
• North Queensland and Darwin: tomatoes are a dry-season crop, April to September in North Queensland and April to July in Darwin. Basil can be sown all year in the Top End, while marigold and nasturtium open in May, a month after the first tomato sowings.

Growing tomatoes in a pot or planning the whole tomato year? Our tomato hub pulls it together, and How to Grow Tomatoes covers the basics.

Brassicas: cabbage, broccoli, cauliflower and kale

Plant with: onion, beetroot, celery, silverbeet, dill, chamomile, nasturtium, and the woody herbs rosemary, sage and thyme. Keep apart: tomato, strawberry and climbing beans.

The reliable defence against cabbage white butterfly and cabbage moth is fine exclusion netting from the day you plant, and no companion matches it. What flowers add is a population of natural enemies. In the Hort Innovation trials, a one-metre strip of sweet alyssum, cornflower or buckwheat beside brassicas increased ladybirds, spiders, parasitic wasps, brown lacewings, damsel bugs and ground beetles at least 15 metres into the crop. Parasitism of diamondback moth caterpillars more than doubled near the flowers, although pest numbers were so low at the trial sites that the researchers describe the pest result as a trend. One of those wasps, Diadegma semiclausum, lays its eggs only in diamondback moth caterpillars.

• South East Queensland, Northern Rivers, Sydney and Melbourne: cabbage and broccoli are sown February to May in South East Queensland, February to June in the Northern Rivers and Melbourne, and February to June (cabbage) or July (broccoli) in Sydney. Adelaide runs from February or March to July or September, and Perth from February to September. Alyssum and dill windows open in March everywhere in this group, so sow them with the first autumn brassicas and the strip is flowering well before the heads form.
• Hobart and Canberra: brassicas are sown in spring and summer for an autumn and winter harvest, September to January for cabbage in both and November to January for Canberra broccoli. Alyssum is sown September to November in Hobart. In Canberra the alyssum window closes in October, so sow it in September or October, ahead of the broccoli transplants.
• North Queensland and Darwin: brassicas are a dry-season crop, May to August for cabbage, and the companion flowers open in May as well, so sow them together.

Brassicas and clubroot are the strongest reason to rotate. See the rotation section and our clubroot page.

Cucurbits: zucchini, cucumber, pumpkin and squash

Plant with: sweet corn, beans, nasturtium, marigold, and borage near squash. Cucumber also pairs with peas, radish and sunflower. Keep apart: potato, and strongly aromatic herbs such as sage near cucumber. Pumpkin, squash and zucchini are all hungry sprawlers, so the chart keeps them in separate patches.

The most useful job a companion does for a cucurbit is bring in pollinators. Zucchini, pumpkin and cucumber bear separate male and female flowers, so fruit set depends on bees and hoverflies finding the plants. Marigold, borage and nasturtium flowers beside the vines keep them visiting, and our zucchini guide and bee-friendly veggie patch cover the rest. Corn gives a cucumber something to climb and a little shade. Companions do not stop powdery mildew, which follows humidity and crowding, so spacing and airflow still matter, and the pumpkin beetle needs watching whatever you plant beside the vines.

• Melbourne, Hobart and Canberra: Melbourne and Hobart start the vines in October and Canberra in November (Canberra pumpkin in November only). Marigold and nasturtium windows open at the same time or earlier, so sow everything together once frost has passed.
• Adelaide and Perth: the vines open in September in Adelaide and in August in Perth, and nasturtium and marigold are both open from September in each.
• Sydney and the subtropics: the vines open in August (South East Queensland) or September and run on to between December and March. Marigold and nasturtium, open March to October in South East Queensland and the Northern Rivers, cover the spring sowings. In Sydney marigold runs September to March and nasturtium has two windows, March to May and September to November.
• North Queensland and Darwin: cucurbits are a dry-season crop, April to August, and marigold and nasturtium open in May.

Corn, beans and squash

The mechanism behind this trio is explained under classic combinations above. Here is how to fit it to your region. Plant the corn in a block and not a single row, because corn is wind-pollinated and a block sets better cobs. Sow the corn first and add the beans once the seedlings are established. Choose one squash or pumpkin for the ground cover, since the chart keeps pumpkin, squash and zucchini apart from each other.

• South East Queensland and Northern Rivers: corn and squash open in August or September and run to February, and snake beans (September to March) give you a climbing bean that overlaps for most of that period.
• Sydney, Melbourne and Adelaide: a spring planting. Runner beans open in September, corn and squash open in September in Sydney and Adelaide and in October in Melbourne, so plant the trio together once the soil is warm. Snake beans open in November in Sydney and Adelaide and in October in Melbourne.
• Perth: the corn window is short, August to September, because sweet corn fails in extreme summer heat. Squash runs August to October and runner beans September to November, so this is an early spring planting.
• Hobart and Canberra: everything goes in after the last frost, October to December in Tasmania and November to December in Canberra. Runner beans suit the cool, snake beans are not suited, and early-maturing corn varieties are the safe choice.
• North Queensland and Darwin: corn and squash are dry-season crops (squash April to August, corn from March or April), which matches bush beans (April to August) but not snake beans, whose window is September to March. Use bush beans as the bean partner here, because runner beans are not suited to the tropics.

Companion flowers that feed beneficial insects

The flowers that work best for beneficial insects are small, open and easy to land on, and they bloom for a long stretch. In the Hort Innovation trials, sweet alyssum had the longest flowering period, opening about four to five weeks after germination and self-sowing to persist from one crop to the next. Cornflower opens five to six weeks after germination and was the best choice for parasitic wasps. Buckwheat (not on our plant pages) was cheap and fast to flower but the least useful for wasps. The trials used strips one metre wide beside the crop. We have no data on how narrow a border can be before it stops working, so make the strip as wide as the bed allows.

Match the flower to the crop in time. The helpers need flowers in bloom for the whole cropping season, and ideally a few weeks before the first pests arrive. The tables give the sow window for each region. Dill and coriander bolt quickly in warm weather, which is exactly what you want here: let some go to flower and leave them.

Subtropical and tropical: South East Queensland, Northern Rivers, North Queensland and Darwin

In South East Queensland and the Northern Rivers the cooler months from March suit alyssum, cornflower, borage, calendula, dill and coriander, and the warm months from September take cosmos, zinnia and sunflower. North Queensland and Darwin run a single dry-season planting starting in April or May. Cornflower has the narrowest window in the tropics, only May to June in Darwin, so lean on alyssum, marigold and borage there.

Warm temperate and Mediterranean: Sydney, Adelaide and Perth

These three regions run on two plantings a year. In March sow alyssum, cornflower, calendula, borage, dill and coriander for flowers through winter and spring. In September sow marigold, cosmos, zinnia and sunflower for summer. Sydney runs a little longer into summer than Adelaide and Perth for marigold, cosmos and sunflower, and zinnia opens in October there.

Cool temperate and highlands: Melbourne, Hobart and Canberra

Melbourne follows the temperate pattern, with autumn sowings from March. Hobart and Canberra have shorter, split windows. Cornflower is sown March to April and again September to October, and the warm-season flowers go in only after the last frost, October to December in Tasmania and November to December in Canberra. Sow the hardy flowers in early spring so they are blooming when the first aphids arrive.

Under and around fruit trees

The chart lists garlic as a companion for fruit trees, and borage, calendula and alyssum are easy ground-level flowers to grow under the canopy. The Australian trials above were in vegetable crops, so treat flowers under fruit trees as a sensible extension and not a proven result. Companions will not stop fruit fly or codling moth. Those need netting, bagging or traps, as our fruit fly guide and codling moth guide explain. For choosing and caring for the trees themselves, start at our fruit trees hub.

Grow guides for the flowers named here: alyssum, cornflower, calendula, borage, dill, coriander, marigold, nasturtium, cosmos, zinnias, sunflower, yarrow and chamomile. For flowers you can eat as well, see growing edible flowers.

Beneficial insects and what they eat

Most of the insects in a healthy garden are neutral or useful. The ones doing the work are ladybirds and their larvae, green and brown lacewings, hoverfly larvae, parasitic wasps, damsel bugs, ground beetles, assassin bugs and spiders. Our Good Bugs vs Bad Bugs photo guide shows each one next to the pest it is often mistaken for, which matters because several of the helpers look alarming. The table pairs common problems with the helpers that handle them and the flowers that keep those helpers around.

Keeping helpers around comes down to four habits.

• Keep something in flower all season. Helpers that arrive to find no nectar move on. Stagger your flower sowings so there is always a flush in bloom.
• Tolerate a few aphids. Predators and parasitic wasps need prey to breed on. A small colony with ladybird larvae among it is a garden working as it should.
• Avoid broad-spectrum sprays. Products that kill anything that moves also kill ladybirds, lacewings, hoverflies and bees. If caterpillars do get ahead, a Bacillus thuringiensis product such as Dipel affects caterpillars only. Use it to the label and follow our Pest Management Guide.
• Leave some cover. Ground beetles and spiders live at soil level, so mulch and the odd undisturbed corner give them somewhere to shelter between meals. Our mulching guide shows how.

Pollinators are part of the same picture. Our bees section, bee-friendly planting guide and bee identifier cover native bees and honey bees.

How companions fit crop rotation

Companion planting and crop rotation answer different questions. Companions decide what grows beside what this season. Rotation decides what grows where from one year to the next, and it is the only one of the two that breaks soil disease and pest cycles. Verticillium wilt can survive in soil for more than ten years and white rot for twenty or more (see our verticillium and white rot pages), so no neighbouring herb is going to clear either. The two work together when you rotate by bed and plant companions within each bed.

Each year every group moves one bed along, in that order. With three or four beds that gives you a working rotation, and with fewer beds the aim is simply never to put the same family back to back. The companions slot in with the plan.

• Companion within the bed's group. Basil, parsley and marigold go in the fruiting bed, dill and nasturtium in the brassica bed, and lettuce under the tomatoes. Everything in a bed then moves together at the end of the season.
• Keep the permanent flower border out of the rotation. Alyssum, borage, yarrow and the herbs that keep flowering year after year feed helpers continuously, so leave them in place around the edge and rotate only the crops.
• Use marigold as a rotation break. If root-knot nematodes have hit your tomatoes or carrots, sow a dense stand of French marigold in that bed, let it grow for at least two months, then plant the crop in the same spot.

Frequently Asked Questions

See also: How to Grow Tomatoes and Tomato in the Plant Library