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Plants should be watered when they are hungry, a gardening expert says.
The journal New Scientist has recently dispelled some old wisdom about the need to water the garden early in the morning before the day warms up.
It says that is not necessary, and sometimes it is not a good idea - same with watering in the early evening.
NZ Gardener editor Jo McCarroll told Sunday Morning it was one of the many myths that existed in horticulture that is simply not true.
It was "incredible" how much something could be repeated and believed without anyone actually testing it, she said.
McCarroll explained the theory suggested droplets on leaves of plants would act as a magnifying lens, magnifying heat from the sun and scorching the plants.
But in recent years, it had been discovered that the water just absorbed the heat and evaporated - not damaging the plants at all.
"It's one of those urban myths like garlic on the shortest day or peeing on lemon trees, everyone knows them, they're repeated all the time, they're not especially true and they're not especially helpful."
Instead, McCarroll said: "If a plant needs water, water it."
Drought and stress from needing to be watered would be far more harmful to the plant than waiting for a particular time of day to water it, she said.
However, if a gardener had the option of when to water their plants and they were doing so by watering the soil, McCarroll suggested in the afternoon, about two or three hours before sunset.
This was because the soil would stay wet overnight and the plants would have longer to absorb it.
If a sprinkler was being used and foliage was getting wet, McCarroll suggested watering plants in the morning as the sun would dry the foliage out.
Having plants sit wet for too long could "could cause more problems with fungal infections".
"If you are doing something like a sprinkler, water in the morning, if you're going to do something in-ground, I'd water in the late afternoon, but water plants when they are thirsty.
"That is the one important thing to take away."
In winter, growth slowed right down, McCarroll said.
However, if people were wanting to plant some seeds, she suggested doing so in a pot or container.
Broad beans, peas, spinach, silverbeet and rocket were all vegetables that could be planted during winter - but they tended to "hang about" until it got warmer - much like humans, she said.
