So, summer’s here and many gardeners will no doubt be reaching for the watering can, checking the levels of their water butt and wondering if a hosepipe ban is going to spread to their area.
There’s already a ban across Cornwall and parts of Devon, so it’s important to know the best ways to garden to save water, and which plants may be susceptible.
Experts offer the following dos and don’ts of heatwave gardening.
DON’T water during the heat of the day. Early morning when it’s cooler, or evening when the sun has gone down is best, as the plants can hydrate overnight, recommend experts Katie Kingett and Yoko Briggs at The Lost Gardens of Heligan.
Rose specialist Philip Harkness, of award-winning Harkness Roses, says watering roses in the early morning, especially if they are in pots, is better, as the plants get the water they need during the day. “If you water in the evening, there’s more humidity overnight, and that is quite an encouragement for fungi such as blackspot and rust to grow.”
DON’T water the top of the plant. Watering the leaves can burn plants, which need the moisture in their roots. Kingett and Briggs advise: “If you’re growing cucurbits, or plants in a poly tunnel, dig a small terracotta pot into the ground beside the plant, so water goes straight to the root.”
DON’T water plants little and often. This will only encourage roots to come to the surface and then be dried out by the sun, advises Kate Turner, Gardening expert for Miracle-Gro.
DON’T feed your lawn when it’s already scorched. The ground needs to be moist for any feed to work, so unless you have been irrigating your lawn from the start, wait until the autumn to start TLC (tender lawn care). Lawns will nearly always recover during autumn, so it’s more important to look after your plants during this dry season, she adds.
DON’T cut your grass often. Grass won’t grow as much in the heat, so it shouldn’t need to be cut so much. If you do have to mow your lawn, use a higher setting, so you do not damage the plant and its roots, say Kingett and Briggs.
DON’T water the whole garden. Established borders shouldn’t need as much watering, because the roots of established plants will go deeper to find moisture.
DON’T plant in a heatwave. Now is not the time to plant anything other than small plants in containers. The soil will be hard and the roots won’t reach down into the soil, so they will need constant watering and will be stressed by the heat. Wait until the autumn when the soil is still warm, but when there will be a regular supply of rain, Turner suggests.
DON’T water irregularly. “Irregular watering can lead to bitter flavours in fruit and vegetables, and with tomatoes, a condition known as blossom end rot – where the bottom of the tomato turns black.” says Turner.
DO use grey water. If you have a hosepipe ban in your area, you can use ‘grey water’ such as washing up water, so long as you have used a very small amount of environmental dish cleaner, say Kingett and Briggs.
DO protect your plants from the sun in a heatwave. Put them in the shade if the pots are moveable, and in the greenhouse, protect vulnerable plants like seedlings, by either using a lime wash over your greenhouse glass to reflect the heat and light, or by draping a cotton sheet over the windows, Kingett and Briggs suggest. It can also help lettuces and other veg from bolting.
“Ensure you let your plants breathe by opening up your greenhouse and relieving them from the extreme temperatures,” Turner adds.
DO water generously and less frequently. This will encourage roots to stay down in the soil, says Turner.
DO keep soil or compost evenly moist. Soaking dry soil can result in some crops – such as tomatoes – splitting and becoming unusable, she suggests.
DO focus on the plants that really need it. Most important are those in containers, so group them together and place them in the shade if you need to. Feed weekly with a liquid feed, while the soil is damp before use, Turner advises.
DO mulch. If you have certain trees or plants with soil you wish to protect, such as fruit trees or fruit bushes, you can weed and water the soil around them and then mulch with a peat-free compost to keep the ground damp and cool. This helps protect the micro-organisms and mycelial network from being damaged, Kingett and Briggs advise.
DO continue to weed. Weeds will be competing with your plants for water and nutrients, so do continue to get rid of them. If small, hoe the tops off the soil and leave the roots to be baked in the sun, says Turner.
