Two gardens, same street, same plants, same weather, and one gets stripped by pests while the other barely notices. It's a genuinely common complaint, and the explanation isn't luck: insects overwhelmingly target plants that are already under stress, and a stressed plant is disproportionately more attractive to almost every common garden pest than a healthy one growing right beside it.
insects overwhelmingly target plants that are already under stress
The mechanism is real and reasonably well understood. A plant under stress, from inconsistent watering, poor soil, being planted too early into cold weather, or simply being crowded and competing for light, produces measurably different chemical signals than a thriving one. Sap-feeding insects like aphids and psyllids can detect these differences, and stressed plant tissue is often easier for them to feed on and offers better nutrition for their offspring. A struggling plant isn't just more visible to a pest, it's genuinely a better host.
One New Zealand gardener's own experience, shared in a widely-read gardening piece on tomato-potato psyllid, is a good illustration of exactly this. They noticed tomatoes they'd grown themselves from seed seemed far less affected by psyllid than plants they'd bought as seedlings, and their own best guess was that the seed-raised plants happened to be a more vigorous variety. It's one gardener's anecdote, not a controlled trial, and it isn't really a case for seed over seedling specifically, since a poorly-grown, stressed plant raised from seed would be just as exposed as a stressed, bought one. What it does illustrate well is the underlying pattern: the plant that was growing more vigorously was the one pests left alone.
This reframes a lot of pest advice usefully. Consistent watering isn't just about yield, it's pest prevention. Planting into properly warmed soil rather than jumping the gun on a mild spring day isn't just about avoiding frost, it's avoiding weeks of unnecessary stress right when a plant is most vulnerable. Good spacing so plants aren't competing hard for light and nutrients isn't just tidiness, it's one less stressor pushing a plant toward being the one pests find first.
None of this means a perfectly grown plant is immune. Pests still turn up in the best-run gardens. But it does mean that the gap between "my garden gets hammered every year" and "my neighbour's doesn't" is very often less about the pest and more about which garden was quietly under more stress in the weeks before the pest arrived.
This is exactly the gap this site's premium check-ins are built to catch, since a plant sliding into stress rarely announces it loudly, a few days of missed watering, a slightly cold week after planting, and the site's stage-aware nudges exist to flag that kind of thing while it's still easy to fix, before it's turned into the reason pests picked this garden over the one next door.