Cross-Pollination: How It Impacts the Taste and Quality of Crops Like Squash and Sweetcorn

You plant a bed of sweet, golden sweetcorn, dreaming of buttery cobs fresh off the grill. Then harvest time comes, and the kernels are tough, chewy, and not so sweet after all. Or maybe you grow a gorgeous courgette, only to slice it open and find bitter flesh. What went wrong?

Chances are, it’s cross-pollination. And while it doesn’t always cause problems, when it does, it can affect both the taste and quality of your harvest, especially in crops like squash and sweetcorn.

Let’s unpack what’s really going on and how to protect your patch from unwanted flavour surprises.

What Is Cross-Pollination?

Cross-pollination happens when pollen from one variety of plant fertilises the flower of another compatible variety. It’s completely natural: bees, wind, or even your sleeve brushing through the garden can do the job.

The impact of cross-pollination varies. Sometimes it’s harmless. But in certain crops, like squash and sweetcorn, it can produce unexpected and less-than-pleasant results.

Why It Matters for Squash and Sweetcorn

Squash: Bitter Surprises

Squash plants, like courgettes, pumpkins, and courgettes are part of the same extended family (Cucurbita). While they might look different, many can cross-pollinate. The real issue comes in next season’s seed. If you save seeds from a cross-pollinated plant, the resulting fruit might be oddly shaped, inedible, or even bitter to the point of toxicity.

Sweetcorn: Kernel Chaos

Sweetcorn is wind-pollinated, and different varieties (especially sweetcorn vs. drying corn) can easily mix. When this happens, you end up with cobs that are starchy instead of sweet, or kernels that don’t develop properly.

How to Prevent Cross-Pollination

Space Varieties Properly

Keep different types of squash or sweetcorn as far apart as possible if you want to save seed or avoid flavour compromise. In smaller gardens, that’s not always practical, but every metre helps.

Use Physical Barriers

• Grow under netting or mesh to reduce pollinator access between varieties.
  
• In greenhouses or tunnels, plant only one type per space to limit exposure.

Control Timing

Stagger sowing dates so that different varieties flower at different times, reducing the chance of cross-pollination.

Hand Pollinate

In squash, you can hand-pollinate to control which pollen fertilises which flower.

• Pick a male flower and gently brush its pollen onto a female bloom.
  
• Then bag the flower (with fine mesh or soft fabric) until the fruit starts to form.

Buy Fresh Seeds Each Year

If you’re not planning to save seed, cross-pollination isn’t as much of an issue for taste, except in the case of sweetcorn. Buying fresh, pure-variety seed each season ensures consistent flavour and quality.

When Cross-Pollination Doesn’t Matter

Tomatoes, beans, and lettuces are mostly self-pollinating and don’t easily cross, so no worries there. But when it comes to open-pollinated squash or wind-pollinated sweetcorn, it pays to take precautions if flavour and consistency matter.

Cross-pollination might sound like a problem for big farms or seed breeders, but it affects every grower who values flavour, reliability, and seed saving. If you’ve ever ended up with oddball squash or disappointing sweetcorn, chances are this was the culprit.