There’s another heatwave on the way and gardeners will be doing everything they can to keep their beautiful plants and flowers alive. But some of these frantic efforts could actually end up doing their thirsty gardens more harm than good.
Most plants will start to feel heat stress at temperatures in the high twenties and prolonged exposure at these levels can cause wilting, leaf scorch, stunted growth and even death.
Temperatures in London are set to take a quick dip before shooting back up to around 28C by the end of next week. The Met Office 3-month outlook suggests that this trend will continue with temperatures likely to be higher than normal.
‘Morning watering is ideal’
While you might think constant watering is the answer, this can actually be damaging when done during high temperatures, say the National Trust. It is best to water plants during the morning or last thing at night to avoid any damage as sun shining on water can act like a magnifying glass and burn the leaves below.
Expert florist David Denyer, from Eflorist, said: “Midday sun evaporates water quickly and can even scorch foliage. Morning watering is ideal. It gives the soil time to absorb the moisture before heat sets in.”
It is also important to remember to water deep and slowly, rather than with quick, careless splashes. Mr Denyer added: “Surface watering doesn’t cut it. Focus on slow, deep watering at the base of plants. For containers, make sure water reaches the roots by soaking the soil thoroughly.”
Plants which are surface-rooting, such as lettuce and tomatoes, can wilt quickly and therefore need to be watered more regularly. Deeper-rooted vegetables like carrots, parsnips and potatoes are more resilient so they don’t need to be watered as often.
Avoid digging in the heat
If water is low in your area, or there is a hosepipe ban in place, it is generally safe to leave watering grass as it will normally bounce back when rain returns later in the year.
The sunshine might also be when most people want to get out and about in the garden but digging around in the flower beds can actually do more harm than good. During the dry weather, digging can totally destroy the structure of the soil which increases moisture loss and disturbs plant roots.
Adding organic matter to soil can also help it to retain moisture which can help it to conserve water during the Summer months.
Create shaded areas for plants
Plants benefit from being given breaks from direct sunlight. Making shaded areas can prevent heat-stress, especially for heat-sensitive flowers with shallow roots or fragile petals.
“Move potted plants to shaded patios, under trees, or behind taller plants,” said David.
He added: “Use garden fleece, parasols, or even an old sheet to shield delicate flowers for the day.”
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