My neighbour, who is a very experienced gardener, recently told me off for watering in the middle of the day, saying that in hot weather it can damage plants. Is this true or just another old wives’ tale? S Pearce, Dublin
The short answer is “it depends”. The long answer is that given Ireland’s mild, moderate climate, you’re not going to cause damage to a plant by watering it in the middle of the day, even slap-bang in the middle of a summer heatwave. In fact, it’s much more likely to suffer damage during the latter as a result of underwatering. But for some reason the myth persists that water droplets left on the leaves and flowers of plants after watering act as magnifying lenses in hot weather, causing scorching of the foliage and the flowers.
However, there are other good reasons not to water at this time of the day. First and foremost is the fact that it’s much less effective because of higher rates of evaporation and transpiration. It’s also wasteful of water, a precious resource in this climate-challenged world of ours. Instead, the best time to water your plants at this time of year is in the cool of the evening, which gives their thirsty root systems sufficient time to properly drink it in.
Failing that, try to do it in early morning, when plants are more refreshed and less likely to be stressed by very hot sunshine and high temperatures. That’s especially true if you’re combining watering with liquid feeding, which again is much better done in the evening or early morning.
RM Block
Apply water gently as a spray, using a rose or nozzle to protect fine root hairs from being damaged, as well as to avoid displacing the surface of the soil or compost
When the growing season reaches late summer/early autumn, many gardeners then prefer to water in the morning rather than in the evening, as this minimises the risk of common plant diseases caused by a combination of high humidity and cooler night-time temperatures.
The way in which you water is also important. Try to direct it close to the base of the plant where it will more easily reach its roots system and is less wasteful. Apply it gently as a spray, using a rose or nozzle to protect fine root hairs from being damaged, as well as to avoid displacing the surface of the soil or compost.
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Make sure also to give enough water, bearing in mind that superficial watering can have the unwanted effect of encouraging plants to produce shallow roots too close to the surface of the soil, where they’re more vulnerable to damage as well as to intense summer heat. But bear in mind that some rainforest species such as tree ferns also need to be misted occasionally, as well as watered at the top of their whiskery trunks where the fronds emerge.
