Why water your lawn?
This lawn suffered badly in the 2018 drought, by autumn it was clear large areas had died. There were some factors stacked against it: The lawn was old, and the grass lacked the vigour to recover. The surrounding brick wall radiated heat and the areas of lawn on a slight slope towards the sun suffered worst. Lawn roots can survive for a while in dry conditions, but not for long if also subjected to baking heat.
Because without moisture, grass may die, and it will certainly suffer long term degradation. Lawn grass is not drought proof, and it does not `always come back`. Repairing a drought damaged lawn is a LOT more expensive than damage prevention.
A different story for this lawn in 2018. Correct use of a garden sprinkler every week or even every ten days meant the roots of the grass never went into deep stress or got close to death. The Lawn had been overseeded the year before and the grass was still full of vigour, it came back into prime condition very quickly once temperatures dropped.
We understand some people feel watering a lawn is a terrible waste of water. We think watering correctly is no more wasteful than washing windows, cars, taking a bath or indeed watering any other garden plant. Everybody is entitled to their opinion, what follows is intended as helpful information for those who want to know how and when to get the most out of a lawn watering programme ensuring the water they do use, is not wasted.
Lawns have a Summer water requirement.They cannot be `drought proofed`, however there are products which can be used which will help your soil absorb and retain moisture. Correct use will help to reduce the amount of rain or irrigation the lawn needs to be given in order to function healthily. These are called `wetting agents`. Please call to discuss if you want further information or advice on them.
So long as there is no `hosepipe ban` lawns can easily be kept out of drought stress and danger from significant damage. The objective should be to keep it out of deep stress & to keep the root system alive. This does not mean applying enough water to keep the top growth emerald green, but if you want to do that the grass will not mind!
Is it a waste of water? In our opinion it is not, it is common for the top layer of soil to dry out a very long time before artesian water and reservoir supplies are under any pressure. It is the top 2 to 3 inches of soil that dry out first, and this is the typical root depth of lawns.
Will it be expensive? No, and certainly it will be hundreds of times cheaper than repairing a lawn which suffers long term drought damage. Do use a sprinkler – there are many available online or in garden centres, they ensure water arrives gently on the lawn in a way that it can be absorbed. Do not use a hose with nothing attached – most of the water will run off or pool and evaporate.
How much exactly will it cost? There is no definitive answer because we cannot tell you exactly how much water your soil type will require. So, let us consider some averages.
Most lawns can be kept in good health during hot and dry weather with 10 Litres of water per square meter of lawn surface per week. So, 100 Sq. M of grass needs roughly 1000 litres.
1000 litres of water usage will add roughly £1 to your water meter bill.
The average tap discharges 6L* of water per minute. So, for every 2 hours and 45minutes the tap is on you are spending roughly £1 and discharging 1000 litres.
You can pace out the area your sprinkler is serving (1 stride = 1M…roughly) and move it once each of the covered areas has had 10L of water. If your tap is running at 6L per minute and the coverage was 10 paces by 8 paces (80SqM) you could calculate 80 times 10 = 800 Litres divided by 6* = 133 minutes of `tap time`
A really simple way of calculating when to move your sprinkler is to place a mall vertical sided container inside its arc: when there is ½ an inch of water or 13mm in the container you can move the sprinkler to the next area.
How to water your lawn
On AVERAGE one hour of sprinkler time twice a week as a good regime. The cost would be roughly £1.60 a week per 100 sq. Metres of Lawn. Even in a prolonged dry spell this will only go on for 6 or 7 weeks.
Our recommendation is to give the lawn 2 doses of 5 litres per Sq. M per week – for most lawns this will mean doing some watering in a different spot a few times a week. But if you find your lawn needs less there is no hard and fast rule that it must have 10L per Sq. M
Get to know your soil. 2 Days after watering, make a hole with a garden fork. Use a finger to test inside the hole for moisture a couple of inches down. If it is dry, water again – if moist, you can leave it another day or two. Remember – the aim is to keep some moisture available to the roots.
Do not water in hot direct sunlight. Evaporation will waste water intended for the roots; it may even scorch the leaf. Ideally early morning watering is best as it does not leave the lawn damp all night – this can potentially encourage certain fungal infections. If early mornings are impossible, late afternoons and evenings are the best alternative.
To get any benefit from irrigating your grass, you need to be generous and get the roots wet. Little and often tends to be ineffectual, so when you do water – be generous.
Many lawns have areas that suffer more than others, parts which enjoy shade will dry more slowly and require less watering.
Water before the grass becomes distressed. Once your lawn has started to show obvious and widespread signs of moisture shortage the soil may be getting dry enough to develop some hydrophobia – permanent dry areas that resist the ingress of moisture. An early / preventative approach to watering will reduce overall water usage.
This does not need to be a big or expensive chore. The aim is not emerald green perfection, but a lawn that can maintain long term health while it survives hot and dry weather. A whole tennis court sized lawn could be maintained in this way for something like £7 a week. This is cheap maintenance of a costly to repair garden feature.
A decent sprinkler can be purchased from around £35; if you do not already have one it will also be useful for getting water to flower beds and shrubs during dry spells.
What if your lawn is SO big that watering is not practical?
Consider irrigating the areas prone to the worst drought distress & concentrating on them.
Back off the mowing frequency and raise your mowing height before the lawn shows signs of moisture shortage.