How to water your garden like a pro in the summer

There's actually a science behind it and lots of us have been doing it all wrong

The recent sweltering summer temperatures have been brilliant for sun worshippers, but for gardeners, not so much.

Reaching for the hose or watering can will be coming naturally to green-fingered residents of Wales who want to keep their lawns, flowers and plants hydrated.

But what is the best way to keep your garden hydrated?

There's actually a science behind it and lots of us have been doing it all wrong.

So we have put together some top tips to water your garden like a boss.

Watering plants in the midday sun

The idea that watering your plants in hot sun damages the leaves is considered by many gardeners to be established fact.

However, according to a study published in New Phytologist there had been very little research into it.

Dr Gabor Horvath, from Hungary’s Eotvos University, who led the research, said: "The problem of light focusing by water droplets adhered to plants has never been thoroughly investigated, neither theoretically, nor experimentally.

“However, this is far from a trivial question.

"The prevailing opinion is that forest fires can be sparked by intense sunlight focused by water drops on dried-out vegetation.”

After both computer and experimental studies, his team determined some plants are more at risk than others.

"In sunshine water drops residing on smooth hairless plant leaves are unlikely to damage the leaf tissue." said Dr Horvath.

"However water drops held by plant hairs can indeed cause sunburn and the same phenomenon can occur when water droplets are held above human skin by body hair."

While the same process could theoretically lead to forest fires if water droplets are caught on dried-out vegetation, Horvath and colleagues added a note of caution:

"If the focal region of drops falls exactly on the dry plant surface intensely focused sunlight could theoretically start a fire,” Horvath said. “However, the likelihood is reduced as the water drops should evaporate before this, so these claims should be treated with a grain of salt."

When to water

According to the Royal Horticultural Society (RHS) the best time to water plants early in the morning to avoid evaporation.

The RHS says: "In warm summer days, evening watering is also likely to be effective, the dry soil soaking it in readily and low humidity at night reducing risk of disease.

"To determine the need for watering, inspect the soil at a spade's depth.

"If the soil feels damp, there is unlikely to be any need to water, but if it is dry, then watering is probably required for some plants.

"Be aware that clay soils can feel damp even when all available water has been used and that sand soils can feel dry even if some water is available.

"For plants in pots, the compost looking paler or feeling dry to the touch and the pot becoming lighter in weight (and consequently more prone to blowing over) are all signs that the compost is beginning to dry and is in need of water."

How to water

It is better to water the garden before drought really sets in, to keep the soil moisture levels even and avoid soil moisture deficits building up, the RHS says.

"Once drought has set in, it is futile to try and remedy this by light watering over a wide area.

"Light watering may encourage surface rather than deep roots, leaving plants more susceptible to drought. Instead, make a single thorough watering of the plants that are suffering.

"Try to water in the cool of the evening or the very early morning, so that less water is lost immediately to evaporation.

"Watering should never be carried out where drainage is poor, as adding water will do more harm than good. Roots are very susceptible to airless conditions, particularly when the soil is warm in summer."

Methods of watering

These the four methods of watering your garden like a boss, according to the RHS:

Sprinklers: These have only limited use in gardens and are mainly used to water the lawn.

Hoses and watering cans: Most garden watering should be aimed specifically at the stem bases beneath the foliage canopy, leaving the surrounding soil dry to help limit weed problems.

Seep hoses: These hoses or pipes with holes in them deliver water accurately to established plants and plants in rows. They can be hidden beneath soil or mulch, which also avoids evaporation losses. They work best on heavy soil where the water spreads further sideways as it sinks than on lighter soils.

Automated irrigation systems: To save time and labour, watering cans and hoses can be replaced by drip or trickle irrigation systems. Only the root zone or top 60cm (2ft) of soil should be wetted - water that penetrates deeper will be inaccessible to most plant roots.

How much water to apply

Light sandy soils require watering more frequently than heavy soils, but less water can be applied at each watering. Heavier, clay-based soils can be watered less frequently, but need heavier applications of water because they hold more water within their structure.

A clay soil in which plants are wilting might need 81 litres per sq metre (17.5 gallons per 10 sq ft), and a sandy soil in which plants are wilting might need 60 litres per sq metre (12.2 gallons per 10 sq ft).

Water can also be saved by applying it to the base of the plant rather than over a wide area. As a general guide, up to 24 litres per sq metre (5.2 gallons per 10 sq ft) every seven to 10 days will be sufficient to maintain plant growth.