Companion Planting: Five Smart Crop Pairings For Bigger Harvests
On a half-hectare plot in Goromonzi, 48-year-old farmer Memory Mutsvaira bends over a bed of onions and carrots planted in tight rows. Between the lines of green, she’s slipped in marigolds and a few herbs – not for beauty, but because she’s heard they can help keep pests down and make better use of her limited land.
Across allotments in Britain and gardens around the world, this idea has a name: companion planting – the practice of growing certain crops together to boost harvests, share space, and sometimes confuse pests. Many of the principles translate directly to Zimbabwean vegetable beds and small plots, especially where land and inputs are tight.
A recent guide from UK-based gardener, teacher, author, and ‘no dig’ pioneer Charles Dowding, shared via PA Media and Yahoo, lays out practical veg combinations in his new book, Grow Together. Gardening broadcaster and author Pippa Greenwood also weighs in on how clever crop pairing can help deter some pests and attract beneficial insects.
What Is Companion Planting – And Does It Really Work?
At its heart, companion planting is about support, not magic. It’s using plant partnerships to:
- Make better use of limited space.
- Stagger crops over time in the same bed.
- Encourage beneficial insects like pollinators and predators.
- Sometimes confuse or deter certain pests.
Dowding argues that many crops which taste good together on the plate also grow well together in the soil: basil with tomatoes, beetroot with onions, dill with cucumbers, lettuce with rocket.
He focuses on multi-sowing, succession planting, overlapping plantings, and interplanting to boost production – using timing and spacing so that one crop is finishing just as another is getting started.
FFA Explainer:
Companion planting doesn’t mean every pest will disappear or that one miracle flower will save a crop. It’s a set of practical strategies: sharing space wisely, overlapping crops in time, and using flowers and herbs to attract helpful insects. Think planning, not magic.
Can Companion Plants Really Deter Pests?
On this, even the experts disagree – and that’s useful for farmers to hear.
Pippa Greenwood, who runs a gardening business selling plants and biological pest controls, believes some combinations can help confuse or repel certain insects.
She points to classics like:
- Onions and carrots: Growing onions in alternate rows between carrots, she says, can deter carrot fly because the smell of the onion masks the scent of the carrot. Likewise, the carrot smell confuses the onion fly.
- Marigolds with tomatoes and cucumbers: French marigolds appear to help repel or confuse glasshouse whitefly. Their flowers also attract hoverflies and other beneficial insects whose larvae feed on aphids.
“You want pollinating insects to come into the area because they are going to pollinate your crops,” Greenwood notes. Open, scented flowers mixed into veg beds can draw in those “helpers”.
Dowding, however, is more cautious about promises of pest control through smell alone. He says he has tried many of the classic combinations and has “never found that onions keep carrot root fly off”, and he doesn’t believe nasturtiums reliably pull caterpillars away from cabbages.
“I’ve never yet heard that anyone growing nasturtiums doesn’t have any problem with caterpillars on their brassicas,” he says. In his experience, nasturtiums get eaten and brassicas still host caterpillars – sometimes even more, because there’s more food for them.
For Dowding, the real power of companion planting lies in planning space and time rather than relying on scent-based pest control alone.
Five Crop Pairings To Boost Your Harvest
In Grow Together, Dowding shares 50 planting partnerships. Here are five highlighted in the article that any vegetable grower – from a Chitungwiza backyard gardener to a community garden in Bulawayo – can adapt.
1. Celeriac And Garlic: Using Timing To Share A Bed
This partnership, Dowding explains, is all about timing, not chemistry.
His method:
- In October (Northern Hemisphere autumn), he plants garlic in lines across a bed.
- Those lines leave clear spaces between them.
- By May, the garlic still has about a month left to grow.
- At that point, young celeriac plants are ready, and he slips them into the spaces between the garlic rows.
The garlic continues to grow and is harvested soon after, just as the small celeriac seedlings are putting roots down. Once the garlic is out, the celeriac can take off, already established.
For Zimbabwean conditions, the specific months shift with seasons, but the principle stands: plant a slow-maturing crop (like celeriac, or locally perhaps carrots or beetroot) into gaps while an earlier crop (garlic, onions, early greens) is finishing its final month. You harvest twice from one bed without over-crowding either crop.
2. Spring Onions And Beetroot: Two Harvests From One Space
This is another example of clever overlapping.
Dowding:
- Multi-sows both spring onions and beetroot at the same time, in April, May, or June.
- He spaces beetroot clumps at about 30cm intervals.
- In the gaps between those beetroot clumps, he plants clumps of spring onions.
Because spring onions grow upright and don’t sprawl, they don’t swamp the beetroot. By early July, he harvests a good flush of spring onions. Later in the season, with the onions gone, the beetroot matures and fills out the bed.
This approach can be adapted with other combinations too – for example, pairing upright onions with slower root crops in our own gardens and nutrition gardens, maximising space and time.
3. Chard And Dwarf French Beans: Beans First, Leaves Later
Here, the beans and chard share the same ground, but not the same main season.
Dowding recommends:
- At the beginning of July, transplant dwarf French beans into rows.
- At the same time, direct-sow chard in between or alongside those rows.
- The beans grow fast, produce their crop, and then finish.
- When they’re done, he cuts the bean plants off at ground level and moves them to the compost heap, leaving roots (with nitrogen nodules) in the soil.
- With the beans gone, the young chard plants suddenly have space and nutrients to power ahead.
He notes that the chard benefits from the nitrogen left behind on the bean roots. In a Zimbabwean context, a similar principle applies with cowpeas and leafy greens, or sugar beans and rape/choumollier – early beans, then a follow-on leafy crop taking advantage of the improved soil.
4. French Marigolds With Tomatoes: Flowers As Bodyguards
Pippa Greenwood points out that marigolds planted with tomatoes and cucumbers can help repel or confuse pests like glasshouse whitefly, while also attracting beneficial predators like hoverflies whose larvae eat aphids.
Dowding adds a specific twist with French marigolds, which he calls “great – they’re small, compact plants”. He says:
“I’ve got 250 of them on the go now. I just dot them around the garden, often on the ends of beds and underneath plants as well.
I plant them around my tomatoes because they secrete something called limonene, which deters aphids.”
For greenhouse tomatoes, tunnel houses, or even open-field tomato beds in Mutasa or Murehwa, tucking French marigolds along row edges could help reduce aphid pressure and bring in allies like hoverflies and ladybirds. At the very least, they add colour and extra nectar for pollinators around the plot.
5. Florence Fennel Between Ridge Cucumbers: Faith In The Future
Fennel has a bad reputation as a poor neighbour in some gardening lore, said to stunt nearby plants. Dowding disagrees.
“Fennel has always been famous for not getting on with any other plant, and I just don’t find that is true. It’s very happy growing close to other plants and other plants are happy growing close to it,” he says.
He recommends a partnership of Florence fennel with ridge cucumbers for late-summer and autumn harvests:
- The cucumbers are sown and established first, covering the ground with foliage in late summer.
- He sows fennel in late July, then plants it out in mid-August among the cucumber foliage.
- He trims off any diseased cucumber leaves to make space and gives the young fennel plants occasional water.
- Within about a month, the cucumbers have finished cropping and can be cleared.
- By then, the fennel plants are already of decent size and continue to grow, ready for an October harvest.
“It feels a bit like an act of faith sometimes,” Dowding admits, because you’re tucking small fennel plants under big cucumbers and trusting they’ll catch up once the first crop is done.
Again, the principle is timeless: let a sprawling early crop (like cucumbers or even pumpkins) use the space first, then underplant a slower, later-maturing crop that will take over as the first one fades.
How Can Zimbabwean Growers Use These Ideas?
For smallholders and home gardeners in Zimbabwe, companion planting ideas from Somerset allotments might seem far away, but the logic travels well.
Key takeaways:
- Think in layers of time: Use quick crops (spring onions, lettuce, beans) to fill space while slower ones (beetroot, celeriac, cabbages) are getting established.
- Match plant shapes: Upright crops like onions can slot between bulkier root crops without competing too much.
- Use legumes to feed leafy follow-ons: Beans and cowpeas leave nitrogen nodules on roots, which leafy crops can benefit from once the legumes are cut.
- Add flowers as helpers: Marigolds, nasturtiums, and other open flowers bring in pollinators and predators; just don’t expect them to be a magic shield against pests.
Extension officers and agroecology groups already promoting intercropping and agroecology can borrow specific pairings like onions with carrots, beans with greens, or marigolds with tomatoes, adapting timing to local seasons.
For women and youth leading nutrition gardens under NDS1-aligned programmes, these methods offer a way to turn one small bed into two or three staggered harvests, making limited land go further while supporting pollinators and beneficial insects.
Back in Goromonzi, Memory bends to pull a handful of spring onions from between her beetroot and smiles. Two crops, one piece of land, and a few marigolds nodding between them. It’s not magic. It’s simply growing together – with a bit of planning, and a lot of promise inside each small partnership in the soil.
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