How to water your garden during a drought

Telegraph

a day ago

Our gardens have been far from tranquil and relaxing during these intense periods of hot weather. Even in the shade, there can be little comfort found during the day, making gardens uncomfortable for us, let alone our plants. Watering can seem relentless, and with a heightened awareness of the scarcity of this resource – particularly due to the hosepipe bans that are in place in parts of the country – how do we water wisely to keep our plants healthy, while avoiding unnecessarily high water bills? Here's some advice to keep in mind.
Greenhouses
The greenhouse is one of the most difficult parts of your garden to manage during the high summer, requiring regular attention. The past few weekends have seen the greenhouses at West Dean reach over 40C, making even the cactus squint. In high summer, if plants are grown in containers, they should if possible be moved out of these hot houses into a shady part of the garden, to prevent them from drying out. If plants are to be kept in your greenhouse, then water first thing in the morning, and saturate the roots to hydrate them for the day ahead. A second watering during the early evening will help to reinvigorate your plant to avoid unnecessary stress, as temperatures remain high into the evening.
Avoid watering your tomatoes in the evening, however, as damp foliage at night can cause perfect conditions for blight. Fruiting crops such as aubergines, tomatoes and peppers dislike fluctuating moisture levels as it can affect the development of the fruit; more consistent moisture level at the root will produce healthier plants and fruit. Cooling the temperatures down in your greenhouse can be achieved by painting a shading product onto the outside of the glass, which will reduce the amount of heat and light that enters the structure, resulting in the plants lasting longer between watering.
Heat stress
Plants can wilt from heat stress in the summer due to the warm temperatures, but can be moist at the root. Use your finger, and insert it into the root ball to detect any moisture levels. On hot days, if some of your plants are wilting, yet there is moisture at the root, they will soon recover when temperatures cool. Avoid adding more moisture to the root ball if it is saturated already, as extra watering will only cause more stress to the plant, and will potentially kill it.
Grouping pots
Grouping pots together will help to make watering more time efficient, with the extra humidity caused by dense foliage helping plants through tough times. During spells of particularly hot weather, move pots away from their sun-baked spots to areas in the shade, to help plants survive these difficult times. These periods of intense heat will damage most plants, but once the worst is over, it can be business as usual, and you can return them to their original spot. Acers in pots are especially vulnerable and should be protected. The damage comes from two fronts: scorched foliage by the sun and drying winds, coupled with high temperatures within the pot, causing root damage. Acers in pots are best placed in a sheltered, shady spot in the garden, and not allowed to dry out during the summer.
Group plants with similar requirements together to help with your watering routine, and to avoid accidentally watering plants that don't require it; succulents and Mediterranean herbs will require less water than bedding plants, for instance, so group the pots of thirsty plants together.
Top-dressing your containers with bark or gravel that is several centimetres deep, will also slow down evaporation; water well before applying the mulch. For large containers that cannot be moved into the shade, try draping an old net curtain or horticultural fleece over the plant, which will filter the light and reduce evaporation during times of excessive heat.
How to water
When it comes to a watering technique, most of the water is required at the root, not all over the leaves. A watering can is an efficient way to water your plants, as the amount of water that you apply can be easily controlled. Watering with a hosepipe – where it is allowed – can save time, but it is harder to gauge how much water you are applying. You'll be surprised how much water is given to a plant by just a few seconds from a hosepipe. To understand how much water you are giving your plant through a hosepipe, get a feel for how long you water the plant, and then hold that hosepipe over a bucket for the same amount of time. The amount of water that you are giving your plant will be visible within the bucket (you may be surprised by the high volume of water you are applying). Moreover, most of this water will drain out of the base of the pot and be wasted. Containers can be placed in a saucer, which will act as a reservoir to be utilised by the plants during hot spells.
Automatic systems
Irrigation techniques cover a vast spectrum: from an upside-down plastic drinks bottle with the bottom removed and filled with water as a reservoir, right the way through to soaker hoses on a timer, or a remotely monitored watering system controlled by an app. The most effective and efficient way to irrigate your plants is through a drip irrigation system, which pumps water through pipework to nozzles that are inserted into a root ball. This delivers water gradually, to meet the plant's needs with no wastage. Ultimately, there are pros and cons for automated systems, and they suit some people more than others. The level of sophistication that is delivered with these systems is also wide-ranging, as is the budget required to purchase them. I discovered that a solar-powered system that drew water from a recycled bottle from a water dispenser (the ones you find in an office), worked incredibly well and cost less than £50.
Lawns
In all honesty, it's very hard to maintain grass without copious amounts of water during prolonged periods of hot and dry weather. Tougher grasses will recover in the main, but finer lawns may suffer. Weeds tend to be more resilient than turf, with deeper roots, so they can make your lawn look untidy. Simply mow the tops off, avoiding damaging the grass by cutting with a higher-set blade. Scarify in the autumn to remove thatch and promote a more robust turf, or consider leaving some areas to grow long. Well-kept lawns are becoming increasingly hard to maintain and justify in such conditions; it's not what everyone likes to hear, but I'm afraid it's a harsh reality.