Nasturtiums in the vegetable garden: the old trick for better harvests

When planning a vegetable garden in spring, tomatoes, courgettes and lettuce are usually the first crops that come to mind. Yet an old trick, once taken for granted by earlier generations, is now returning to the spotlight: sowing one simple flower among the beds can protect vegetables, attract pollinators and produce noticeably better harvests – all without chemicals.

Why this traditional gardening wisdom is making a comeback

For a long time, artificial fertilisers and sprays dominated the home garden. As a result, many natural relationships between plants were overlooked. Now, more people are returning to companion planting, living soil and beneficial insects rather than poisons. This is exactly where nasturtiums show their greatest strength.

They were once a familiar sight in almost every cottage garden: bright, trailing or bushy nasturtiums growing among beans, peas, lettuce and brassicas. Today, more gardeners are once again reaching for their seeds, not simply because they look attractive, but because they fulfil several roles in a vegetable bed.

“Nasturtiums are an ornamental plant, a pest trap and a pollinator magnet all in one – making them a small multitool for the vegetable garden.”

The best time: why starting in March matters so much

As soon as the hardest frosts have passed and the soil begins to warm, the busiest period in the garden starts. From March onwards, nasturtiums can be started indoors or sown directly, depending on the region and weather conditions.

Starting early gives the plant a head start: it develops strong roots, plenty of foliage and its first flowers before the vegetable crops grow properly. Its protective shield is therefore already in place when aphids, caterpillars and other pests appear.

• From March: Start seeds in pots on a windowsill or in a cold frame
• From April/May: Sow directly outdoors in warmer areas
• From a soil temperature of around 10 °C: Germination is considerably more successful

Nasturtiums as a secret shield: the sacrificial plant

The key trick behind this flower is that it serves as a deliberately positioned “sacrificial plant”. Its leaves and shoots are incredibly appealing to aphids, especially black aphid species that commonly attack peas, beans and young shoots.

How nasturtiums divert pests away from vegetables

Rather than moving onto French beans, broad beans or young brassica plants, aphid colonies preferentially settle on nasturtiums. In the most literal sense, the plant draws the trouble towards itself.

The principle is straightforward:

• Aphids fly in and search for appealing food.
• To them, nasturtiums resemble a brightly advertised buffet.
• The aphids gather on this plant and largely leave the vegetables alone.

As a result, vulnerable crops remain far better protected. A close look often reveals that the nasturtium is covered in black aphids, while the beans and peas beside it remain remarkably clean.

Natural pest control without chemicals

The benefit goes even further. Wherever there are large numbers of aphids, their natural enemies soon arrive: ladybirds, lacewings, hoverflies and their larvae. They find abundant food on nasturtiums and reproduce in greater numbers.

“Nasturtiums act like a feeding station for beneficial insects – anyone who grows them in the garden is raising their own pest controllers.”

Over time, a balance develops: plenty of aphids, and plenty of predators. The infestation is much less likely to spread through the rest of the vegetable patch and can often be kept under control entirely without sprays. If preferred, heavily infested nasturtium shoots can simply be cut off and disposed of with household waste – removing the main surge of aphids at the same time.

Better harvests: flowers as a signal for bees and more

Nasturtiums do more than act as a pest trap. Their large, striking flowers in yellow, orange and red stand out from a distance – not only to us, but especially to bees, bumblebees and other pollinators.

A colourful landing strip in the vegetable garden

Amid a lush green bed, the blooms look like colourful landing points. They provide generous amounts of nectar and pollen, which is why they are continually visited. Placing the plants strategically among vegetables turns the entire area into an appealing destination for pollinators.

The insects do not stay solely on the nasturtiums. They naturally visit nearby flowers too:

• Tomatoes in beds or containers
• Strawberries around the edges
• Squash, courgettes and cucumbers
• Fruit trees near the garden

More pollination generally means more fruit, better-developed pods and a significantly higher overall yield – particularly in dry or still years, when pollen is not easily distributed by itself.

Just as effective on a city balcony as in a large garden

Whether it is a small back yard, a raised bed on the patio or a spacious kitchen garden, the effect is similar. In densely built-up urban neighbourhoods, flowering plants for pollinators are often scarce. Combining nasturtiums with vegetable plants creates a genuine refuelling stop for insects – and provides better harvests in return.

How to use nasturtiums effectively in a vegetable bed

Choosing the right position between the rows

Placement has a major influence on the result. Rather than planting nasturtiums in any unused corner, it is worth distributing them thoughtfully.

• Around bed edges: As a colourful border that intercepts pests
• Between rows: Especially among beans, peas, brassicas and cucumbers
• Near fruit trees: As an attraction for pollinators
• In raised beds: Use trailing varieties that spill decoratively over the edge

As a rough guide, place a small group of two to three seeds every 30 to 40 centimetres. This creates a loose network across the bed without allowing the nasturtiums to overwhelm the vegetables.

Watering, soil and care – it could hardly be easier

Nasturtiums are considered uncomplicated plants. They tolerate many soil types, provided the ground is not waterlogged. During their early stage, they appreciate regular but moderate watering. The soil should remain slightly moist rather than soggy.

“Important: water directly at the roots rather than constantly showering the leaves – this reduces fungal risks for every plant in the bed.”

In rich, heavily fertilised soil, nasturtiums mainly produce luxuriant green growth and may sometimes develop fewer flowers. Those who value blooms and insect-friendly planting should avoid over-fertilising. A little compost is generally more than enough.

What many people do not know: cooking, health and choosing varieties

Alongside all their benefits in the bed, nasturtiums offer further advantages. The whole plant is edible: its leaves, flowers and even its still-green seeds.

• Leaves: Mildly hot, similar to cress, and ideal in salads
• Flowers: Attractive, edible decoration with a peppery flavour
• Seeds: Can be pickled as “false capers”

Nasturtiums are also valued in herbal medicine, partly because of their pungent mustard oils, which may have antibacterial effects. For the home garden, the key point is simple: sowing them provides not only a protective system and better harvests, but also an interesting kitchen ingredient.

When selecting a variety, it is worth considering both growth habit and colour. There are trailing types that are ideal for climbing along fences or canes, as well as compact, bushy varieties that remain as colourful cushions in the bed. This makes it possible to choose the right “tool” for each garden setting.

Nasturtiums as part of a living garden

Anyone who consistently includes nasturtiums in their plans from March will soon notice the difference: less trouble with aphids, more buzzing in the beds, stronger harvests and a clear visual improvement. The plant almost forces you to stop viewing a garden as a sterile production space and instead see it as a small ecosystem in which every species has a role.

That is why it is worth looking through the seed box once more before the rows of carrots, beans and tomatoes are finally decided. From March onwards, a few handfuls of seeds from this old-fashioned, almost forgotten flower can change the entire course of the vegetable-growing season in a remarkably simple way.