Gardeners are being advised to adopt a soaking method to protect plants during heatwaves, according to experts. The technique involves watering plants the night before a predicted hot day, ensuring the water penetrates the root zone, then watering again early the following morning before temperatures rise.
Dr Brett Summerell, Chief Botanist at the Royal Botanic Gardens, has urged people to "bust that myth around watering in the middle of the day." He explained that if a plant is short of water, careful watering to the soil and root system can alleviate heat stress, though foliage should be avoided to prevent leaf burn.
Mulching is also recommended to retain moisture, with organic mulches like wood chips or straw being preferable to reflective or lighter-coloured options. Dr Summerell noted that while pebble mulch is aesthetically suitable for succulents, it can become much hotter than straw mulches.
Plant selection is key for heat resilience. Succulents, cacti, and plants from Mediterranean or South African climates are well-adapted to dry, intense heat. For edible crops, more frequent watering—potentially multiple times a day—may be necessary to avoid bitter produce.
Container gardeners should choose sealed, light-coloured pots to reduce heat absorption, as terracotta and black plastic pots lose moisture quickly. Moving pots to shaded areas before heat strikes can also help. For plants in garden beds, temporary shade structures such as beach umbrellas or shade cloth can provide protection from the intense midday and afternoon sun.
Additional products like water crystals and leaf sprays can be used as part of a regular plant-care regime before heatwaves. Water crystals should be pre-expanded and added to the root zone, while leaf sprays like Yates Drought Shield create a protective polymer coating.
