Gardeners are being urged to avoid making one mistake before temperatures rise again next week. From August 8, the UK has been forecast highs above 30C, according to maps by Netweather.
However, during periods of hot weather, one common gardening treatment may be a “bad idea” as it can be rendered completely ineffective. Even though fertiliser is known for giving plants and flowers much-needed nutrients, Linda Ly, the founder of the gardening site Garden Betty, advised people against using it during extreme heat. This is because the heat can cause plants to enter dormancy, so they cannot absorb nutrients.
She wrote: “During periods of drought or heat stress, fertilizing your plants is generally a bad idea.” In their semi-dormant state, plants aren’t able to use the nutrients, so she recommends leaving them until temperatures return to normal.
However, to ensure they can absorb the fertiliser once temperatures cool back down, she advised focusing on hydration. Water the plants throughout the heatwave so the soil is evenly moist, without drowning them.
Ms Ly also recommended ways to protect plants during the heatwave, such as using mulch and a shade cloth.
She wrote: “You can help your plants along by making sure there’s a good layer of mulch around the root zone; this stabilizes the soil temperature and reduces the amount of moisture lost through evaporation.
“Hanging a shade cloth or light-colored bed sheet above your plants can also offer respite from the heat.”
When temperatures cool back down, she recommends applying an organic slow-release granular fertiliser, and then watering it again to distribute nutrients throughout the soil.
The fertiliser can be sprinkled around the base of the plant and spread through the top inch of soil with a small hand rake or trowel before watering.