Horticulturist Peter Dowdall warns against shallow watering during hot weather, explaining how deep soaking protects plants better than frequent light watering during a heatwave07:52, 28 May 2026The UK's record for its hottest May day was broken for the second time this week, with temperatures expected to remain around 30C heading into the weekend. However, one gardening expert has warned against a common watering blunder that "nearly everyone makes" during spells of intense heat.‌Horticulturist and broadcaster Peter Dowdall, widely recognised as The Irish Gardener, has urged homeowners to resist this temptation going forward.‌Speaking to this reporter, he said: "The biggest watering mistake nearly everybody makes during hot weather is watering little and often. It feels logical because people see plants looking stressed in the heat and immediately reach for the hose or watering can.‌"But very often they are only wetting the surface of the soil, and that can actually make plants weaker over time."Peter explained that shallow watering simply encourages shallow roots, and that if moisture only reaches the top layer of soil, the roots will remain close to the surface as a result.‌He went on to explain that the plant will then dry out again "very quickly" once another warm or windy day comes along."You end up creating plants that become dependent on constant watering," he added.Peter, who has spent 30 years working on Irish gardens, believes the most important long-term lesson gardeners need to learn is to plan more seriously for periods of heat and dry weather. He noted that the climate was changing and becoming more resilient, adding: "A huge part of that comes back to soil health and soil structure. Healthy soil holds moisture far better naturally."‌Peter stressed that improving soil should be viewed as a fundamental gardening necessity rather than an optional extra.Underlining its significance, he continued: "If you improve the soil properly, plants become healthier, stronger and far better able to cope with periods of stress."One of the simplest things gardeners can do is mulch around plants. A good layer of organic mulch helps suppress weeds that compete with plant roots for moisture, while also slowing water loss from the soil through evaporation."‌Rather than reacting to struggling plants during hot spells, Peter encouraged gardeners to focus on creating conditions where plants can naturally cope better.He explained that one deep soak was "worth far more than five quick splashes" and that moisture needs to penetrate deep into the soil where roots are actively searching for it.‌The expert also highlighted that timing was critical, warning that watering during the height of a scorching day was "incredibly inefficient" as a significant amount would evaporate before reaching the roots.According to Peter, early morning or late evening are the optimum times to water plants.On a separate note, he reassured gardeners not to worry should they spot their lawns starting to turn brown during dry periods. He said: "A lawn going brown does not necessarily mean it is dead. Grass is remarkably resilient and forgiving and in many cases it recovers perfectly well once rain returns."Article continues belowYou can read more seasonal gardening advice from Peter Dowdall, The Irish Gardener, here