It seems so simple – and yet you should know important rules when watering a grass area. The appropriate time interval, the right time of day and the optimal amount of water play a decisive role in ensuring that the plants develop a deep, healthy root system and that weeds don’t stand a chance. In six important tips we explain how you can optimise the water supply.
If you want to sprinkle your lawn at the beginning of the season, you should not wait too long before doing so. If the grass already shows yellow or brown patches, you have clearly missed the optimal start. But don’t worry: the roots are usually still healthy and will sprout again as soon as they get enough moisture. Otherwise, you can repair the lawn with simple means.
Even if it may not turn out to be an English lawn: With the right know-how, there is a good chance that the lawn will be a lush green for a long time.
1) How often should you water the lawn?
The motto “a lot helps a lot” does not necessarily apply to lawns. If you think you have to water the grass area just as often as the vegetables or the neighbouring perennial bed, you are definitely wrong. How often you need to water a lawn depends on several factors. The most important factor – besides the season, rainfall, time of day and age of the grass – is the condition of the soil.
The rule of thumb: a heavy lawn soil should be watered once a week during the growing season, sandy soils about every three days.
Good to know: Roots can be trained to a certain extent in the process. If the soil is watered thoroughly each time, the roots penetrate into deeper layers. This makes them stronger and better able to withstand drought.
Fertilising with potassium has a supporting effect
Fertilising with potassium in early summer also has a positive effect on the roots and accelerates the regeneration of the lawn. A fertiliser containing 30 to 50 percent of the nutrient is recommended.
2) When is the best time of day for watering?
The wet element is precious, and of course you also have your annual water bill in mind. Avoid sprinkling at midday – especially on hot days: about 90 percent of the water can evaporate immediately after sprinkling. Water droplets also stick to the foliage of neighbouring plants. Due to the burning glass effect, sensitive leaves can even be damaged.
The perfect time for watering the lawn is early in the morning. Then the cooler temperatures and the light wind limit evaporation to a minimum. Watering in the morning also cools the lawn in summer, which means less stress for the grass.
If you can’t make it in the morning, you can also turn on the tap in the late afternoon. The plants will certainly thank you. However, a relatively large amount of water evaporates even at this time, as the soil has already warmed up considerably.
Watering in the evening is not advisable. There is a risk that the lawn will not dry sufficiently overnight. Especially with compacted or heavy soils, waterlogging can become a problem.
Fungi and mosses quickly feel right at home in wet lawns. Fungal pathogens (mildew in shady areas, snow mould) also like to spread in a moist environment. Lawn thatch (dead blades and moss between the blades of grass) increases due to too much wetness because the helpers in the soil (the microorganisms) can no longer work properly.
Tip: If you have clayey soil, make sure that your lawn is well aerated. To do this, you can use a special aerification fork, for example, and apply additional sand.
Save water when sprinkling the lawn
A mulching mower helps to ensure that less water evaporates, as the blanket of fine plant material protects against drying out too quickly. Place your sprinkler very precisely so that it does not water areas that do not need water.
3) How long should you sprinkle the lawn?
If you only give your grass a short refreshment, not much is gained. The water does not penetrate deep enough into the soil and the roots remain shallow as a result. Ultimately, the lawn becomes even more susceptible to drought damage. With regard to the ideal time, no general statements can be made: The sprinkler type, the water pressure in the pipe and the soil type determine the watering time.
As a rule of thumb, water your lawn until the soil is moistened to a depth of about 15 centimetres. This corresponds to the depth of a well-developed root system.
Normal soils can usually only absorb a maximum of 10 litres per hour and square metre. If puddles form quickly in the lawn, this indicates a compacted subsoil. In this case, you should water in stages to gradually soften the soil.
By the way: Even a thundershower often does not penetrate deep enough into the soil. Even then, additional watering should be applied.
Testing the ideal moisture penetration
Take a long screwdriver (or similar instrument) and push it into the soil. It should slide into the soil about 15 centimetres deep without resistance. Alternatively, you can poke out a small sample of soil with the spade.
4) How much water does a grass area need?
When sprinkling your lawn, the optimal amount of water depends on the soil type.
10 to 15 litres per square metre is sufficient for a light sandy soil in summer, heavy soils need up to 20 litres.
With a flow meter you can measure the amount of water well. A bit of mathematics is necessary: determine the size of the area that the sprinkler covers. The amount of water needed per square metre is then converted to the total area.
Simple means to measure the amount of water distributed
An empty drinking glass is placed on the lawn before sprinkling. If the water in it is about 1.5 centimetres high, the ideal amount of water has been applied. A little more convenient: A rain gauge measures the amount of water per square metre. In this way you can also determine how long your sprinkler needs to work for about 15 litres.
5) Blast freshly sown lawns
For newly planted lawns, an intense blast of water can wash away the seeds and erode the soil. So be careful with sprinklers that use high water pressure. Until the grass takes root, the gentler, oscillating sprinklers are a better choice.
Keep the top centimetres of soil moist, but not wet, for newly sown grass seed. Water gently until the blades are about seven centimetres high.
Newly sown grass should be watered daily for about 15 minutes for the first two weeks – during a hot spell, two daily waterings are advisable. Check that the soil surface is intact so that the grasses can anchor themselves well.
6) The right irrigation technique
Relaxed watering with a timer
Who hasn’t experienced it: the sprinkler is set in motion and you look at the clock. What happens all too often, however, is that you suddenly get distracted and then completely forget that the water is running and running. You can take precautions against this: Get yourself a timer that saves you from having to think.
The timer is connected directly to the garden hose. It automatically switches off the water after a preset time. Some timers also measure the flow rate in the process, so over time you’ll know exactly how much water your lawn needs to stay green and lush.
The right sprinkler system
A garden hose with a sprayer may be all you need on a miniature lawn. However, a sprinkler connected to a garden hose is the tool of choice in most cases.
Pulsating sprinklers are best suited for large areas. They distribute the water almost horizontally at high speed, so that wind and evaporation do not have such an effect. A circular sprinkler rotates continuously and is very popular with children (and dogs). It can be used to water curved lawns easily. The rotation can usually be flexibly adjusted from 20° to 360°. The impulse sprinkler has only one nozzle with which it distributes the water gradually in a circular pattern. Oscillating sprinklers, which spray the water straight upwards, are less favourable in terms of evaporation and wind, but they too usually serve their purpose. A swing sprinkler or square sprinkler has an elongated swing arm with several nozzles.
An automatic, permanently installed irrigation system with a timer, retractable sector sprinklers and the appropriate supply lines is, of course, the high-end solution. This investment is worthwhile if the lawn is newly laid and the area is to be maintained for many years. However, a plan is absolutely necessary for this. Underground water pipes to the sprinklers must be drawn, and of course all zones in the garden should be reached equally. Of course, there is also a lot of useful additional technology to purchase here, for example soil moisture meters and smart watering computers.