Techniques
Pollination
The transfer of pollen that lets a flower set fruit — done by insects, wind or by hand — essential for crops like courgettes, beans, tomatoes and fruit trees.
Pollination is the moment a flower gets the pollen it needs to turn into a fruit, pod or seed. Without it, a plant can flower beautifully and still produce nothing. Different crops manage this in different ways, and knowing which is which helps you spot — and fix — problems in a UK garden.
Insect, wind and self-pollination
Many crops rely on insects, mostly bees and hoverflies, to carry pollen from flower to flower. Courgettes, squashes, runner beans and most tree fruit fall into this group. Others, like sweetcorn, are wind-pollinated — which is why you grow it in a block rather than a single row, so pollen drifts between plants. A third group is largely self-pollinating: tomatoes, peppers and French beans pollinate within each flower, often just from a gentle breeze or vibration, so they set fruit even indoors or in a greenhouse.
The courgette example
Courgettes are the classic beginner puzzle. Each plant produces separate male and female flowers. The female flower has a tiny fruit (a swelling) behind the bloom; the male sits on a plain stalk. A bee needs to carry pollen from a male to a female for that little fruit to swell. If your plant has flowers but the baby courgettes shrivel and rot, pollination has failed. You can do it yourself: pick a male flower, peel back the petals, and dab the pollen-covered centre onto the middle of an open female flower. It takes seconds and almost always works.
Why poor weather reduces fruit set
In a cool, wet or windy UK spring and early summer, bees stay tucked away — and crops that depend on them suffer. This is a common cause of courgette and runner bean plants flowering happily but setting little fruit. Warm, dry, settled spells bring the pollinators out and the harvest follows. Hand-pollinating on dull days bridges the gap.
Fruit trees and pollination groups
Tree fruit adds one more layer. Some apples, pears and plums are self-fertile and will crop alone. Many are not, and need a compatible partner nearby flowering at the same time — which is why nurseries sort them into pollination groups. Choose two trees from the same or an adjacent group, or rely on a neighbour's tree within bee range. The variety's rootstock controls size, not pollination, so check both when buying.
Help your pollinators
The simplest fix is to invite the insects in. Grow nectar-rich flowers — borage, calendula, lavender, single-flowered dahlias — alongside your veg, avoid spraying open blooms, and leave a few weeds to flower. A garden buzzing with bees pollinates your beans and courgettes for free.
In a UK garden
In a cool, damp UK spring and early summer, poor bee weather is the most common reason courgettes, runner beans and outdoor tomatoes flower freely but fail to set fruit.
Example
Your courgette plant has lots of flowers but no fruit forming — the female flowers aren't being pollinated, so you transfer pollen yourself with a small brush.