Across allotments and smallholdings, a humble companion flower is stepping up. Market gardeners from Brittany to Lincolnshire say it keeps aphids busy, invites pollinators back, and buys time until spring. It costs pennies, needs little care, and fits between tomatoes, courgettes and beans without fuss.
The flower growers rate for tougher beds and fuller baskets
Why nasturtium punches above its weight
Nasturtium (Tropaeolum majus) comes with peppery blooms in orange, yellow and red, but it is more than decoration. It lures bees and bumblebees, feeds hoverflies, shades soil, and acts as a living decoy for sap-suckers. Plant it between rows and you get movement: pests shift off your veg and onto the sacrificial leaves, while pollinators shuttle pollen across your patch.
Market gardeners like it because it reduces call-outs to pesticides and tightens the loop in mixed cropping. The plant sprawls fast, covers bare earth, and sets seed freely. Seeds store well over winter, so a single packet goes a long way.
Place nasturtiums 30–50 cm apart around tomatoes, courgettes, beans and potatoes to divert aphids and draw bees.
How it underpins healthier crops
A bright magnet for pollinators
Those trumpet flowers carry nectar deep in spurs that bees, bumblebees and butterflies reach with ease. More visits mean better fruit set on tomatoes and courgettes and steadier pod fill on climbing beans. In dry spells, the leaves shade roots, cooling the soil and preserving moisture, which keeps flowers and pollinators active longer each day.
A decoy that buys your veg breathing room
Nasturtiums attract colonies of blackfly and greenfly, which prefer the soft new growth. That “trap crop” effect protects broad beans, tomatoes and cucurbits at critical stages. Hoverfly larvae and ladybirds follow the buffet and mop up clusters. You intervene less, and when you do, you target one plant rather than a whole bed.
Let aphids settle on nasturtium for 10–14 days, then cut back the worst stems and bin them to reset pressure on crops.
Plant now and through spring: a plan that fits your climate
We are in the cool half of the year. You can still act. In mild coastal belts and urban microclimates, direct-sow now and protect with fleece. Elsewhere, start seeds under cover, keep them ticking over frost-free, and plant out after the last frost. In spring, sow directly once soil warms.
- Sowing now: use modules under glass or a bright windowsill at 12–18°C.
- Planting window: outdoors from March to May, or earlier under cloches.
- Spacing: 30–50 cm; closer for dwarf types, wider for trailers.
- Position: full sun to light shade; any well-drained soil.
- Watering: regular at the start, then light but steady in hot spells.
- Care: pinch back runners if they swamp nearby seedlings.
| Crop partner | Placement | Likely benefit |
|---|---|---|
| Tomatoes | At row ends and along the sunny edge | Higher pollinator traffic, fewer aphids on growing tips |
| Courgettes and squash | Between hills, 40 cm off stems | Ground cover against weeds, improved fruit set |
| Climbing beans | Foot of trellis, every 60 cm | Hoverflies on patrol, lower blackfly load |
| Potatoes | Along the outside of ridges | Living mulch, fewer exposed gaps for weeds |
| Brassicas | On borders as sacrificial fringe | Pulls whitefly and caterpillars to the edge |
What growers report when they plant at scale
Fewer flare-ups, steadier yields, cheaper seasons
Across mixed market gardens, nasturtium strips bring down aphid flare-ups by noticeable margins. Several growers report fewer rescue sprays and calmer peaks, especially on early broad beans and late tomatoes. Fruit set on courgettes improves when flowers open during cool mornings: bees already work the nasturtium, then move to the squash flowers as they warm.
Expect variation. In a dry, breezy plot you might see light pressure regardless; in a sheltered city garden, colonies can build fast. The decoy still helps because it concentrates trouble where you can act quickly with pruning shears or a jet of water.
Many smallholders budget one £2–£3 packet for 10–15 plants, enough to ring-fence 8–12 m² of mixed beds for a season.
Keep it working through frost and heat
Simple habits that extend the payoff
- Deadhead weekly to keep flowers coming and pollinators interested.
- Mulch under plants to conserve moisture and cool the root zone.
- Thin congested stems to improve airflow after wet spells.
- Remove and bin heavy aphid clusters before they wander.
- Save seeds from plump, green pods that turn tan and drop, then store dry.
In frost-prone spots, a double fleece on cold nights can stretch flowering deep into November. Once a hard frost lands, lift remaining green matter for the compost and keep seeds back for a fast start next spring.
Extra gains you can bank, and the small risks to manage
Edible, useful, prolific—yet easy to steer
Leaves and flowers are edible with a watercress-style kick. They brighten salads and compound butters, and the unripe seeds take well to pickling. The plant also builds biomass, so spent stems bulk out compost with soft, quick-to-rot material.
Expect robust self-seeding; that is handy, but thin volunteers where they crowd slow crops. Slugs love the young plants, so use collars or hand-pick early in the season. In brassica beds, nasturtiums can attract cabbage white butterflies as intended; check the sacrificial fringe weekly and strip off egg clusters before they hatch. People with sensitive stomachs may find the peppery leaves strong; go light at first.
If you start tonight, here is a quick, workable schedule
A 20-minute setup that sets you up for spring
- Sow six seeds per 9 cm pot, two pots per bed you want to protect.
- Label, water, and keep at a bright window above 12°C.
- At first true leaves, prick out to individual modules.
- From March, harden off for a week, then tuck plants at 30–50 cm intervals.
- Ring key crops first: tomatoes, courgettes, climbing beans.
Want to push the method further?
Mix varieties, stack companions, measure the gains
Use a dwarf nasturtium along paths for neatness, and a trailing type up low netting to shade the southern face of a bed. Pair with calendula and borage for a season-long nectar bar. Alternate strips each year to freshen soil and to avoid a single pest zone building up in one corner.
Track results. Note aphid sightings, harvest counts and spray spend. Many gardeners report double-digit cuts in time spent firefighting and steadier harvests across a three-month window. Even if your gains are modest, the maths often works: a £3 seed packet versus two reactive sprays at £8–£15 each, plus the time saved, sits well with tight budgets and busy weeks.
