As the UK braces for a scorching double-plume heatwave from the Continent, with temperatures expected to soar to 30ºC, gardening enthusiasts are being reminded of the vital importance of keeping their pot plants hydrated.
Even during a downpour, your potted garden greenery may still be going without water, since the leafy umbrella they create often deflects rainwater away, even during the torrential downpours anticipated in the next few days.
Leading horticultural guru Simon from leading gardening channel Walking Talking Gardeners enlightens us with a “genius” tip: diligently water container plants regardless of rainfall – a mantra especially crucial amid a sizzling heatwave.
“Plants regulate their temperature, as we do, by releasing moisture,” Simon advises. “They do that through a specialist pore called a stomatal pore, which you can find using a microscope underneath the leaf – with a few on top of the leaf.”
When faced with blistering heat and aridity, plants perspire through these pores to stay cool, with temperatures above 40ºC potentially fatal; therefore, they actively attempt to safeguard themselves.
Simon explains: “The plant will release moisture through the stomatal pores, as we would do in our sweat pores, to cool themselves down so that the temperature of the plant doesn’t go above 40 or 42° – because if that happens, you get denaturation of the enzymes, and the plant will die.”
That’s why, Simon says, on particularly warm days, even if it’s breezy, you should be watering your potted plants at least once a day, and even twice a day if it’s especially hot.
But the million-dollar question is – how can you tell when a plant needs watering?
Overwatering a plant can also be harmful, potentially leading to root rot, leaf discolouration and stunted growth. Excessively damp soil can also foster an environment for mould and fungus growth, further damaging the plant.
The first method to check the soil, naturally, is simply to poke your finger in the soil and feel whether it’s dry or not. But that might not give you a clear idea of how moist things might be down among the plant’s roots.
An alternative test, Simon suggests, is “to do as the old-school gardeners did in the 19th and 20th centuries, when stone pots or terracotta pots were at their most prevalent.
“You would be familiar with terracotta pots and the sound it makes If it is dry. If you tap it with an appropriate stick, the pot will make a ringing sound.
“If it is fully-watered, it would have a dull kind of thud to it. So just by tapping a pot you’ll be able to tell if that pot requires watering or does not require watering.”
That, he declared with pride, is a display of “old-school skill.”