Watering the lawn during the germination and growth phase
For many people, a healthy, green lawn is an absolute must in the garden.
But especially in summer it is often not so easy to keep the lawn fresh and vital: Drought and heat take a toll on the lawn and the grass becomes wilted and brown. The best way to prevent withered, unsightly grass is to water the lawn.
In fact, success in establishing closed, dense lawns depends in large part on how often you water your freshly seeded lawn.
Watering freshly sown lawn
The lawn seeds are in the ground after the lawn has been established and should germinate there as quickly and completely as possible. The first basic requirement for this is an adequate water supply. This is because while the seed relies on its own energy reserves in the form of stored starch until it forms its first root, it is completely dependent on outside supplies for water. It is particularly important that water or moisture is available at all times. Because if lawn seed falls dry, the germination process is interrupted.
The consequences are:
- The uneven development of the lawn
- Varying growth density
- Gaps in the lawn due to partial loss of seed after drying out
Caution: If the seed of the lawn dries out in the early germination stage, the germination process is interrupted, as this protects the seed from deficient development due to lack of water. Once the germination envelope is open, the sensitive radical will be so severely damaged by drying out in a very short time that it will die.
Watering lawn seed
But how often do you have to water lawn seeds in order for them to germinate and grow successfully? With regard to the permanent supply of sufficient moisture, it is not possible to give a blanket answer to this question. Also, the question of how often should rather be broadened and reinterpreted as “how intensively”. Ultimately, it is not the frequency, but the amount of water applied over the long term that determines the success of the lawn seeding. The amount of water needed depends on various factors:
- Frequency and regularity of natural precipitation
- permeability of the soil
- Temperature and solar radiation due to evaporation
- Wind intensity because of additional drying of the surface
As a rough average, one reads in relevant technical literature, again and again, an amount of about two to two and a half liters of water per square meter of lawn and day. Depending on the factors mentioned, however, this value can also deviate significantly upwards or downwards. In the case of continuous rain, no additional watering is certainly necessary, while in dry conditions and high temperatures, 5 or more liters per square meter may well be required.
It is important to keep the area moist throughout the first 3 to 4 weeks after sowing the lawn seeds. Since lawn seeds are only worked into the soil to a depth of about 1 cm, it is sufficient if only the top layer of soil is well moistened. However, be careful not to overwater. The lawn seeds can easily be washed out, which makes it difficult to form a dense lawn.
At this point, the question of how to determine the correct watering quantity and frequency is justified. Unfortunately, there is no generally applicable formula. Instead, you should regularly check the soil moisture after sowing and thus approach the respective water quantities and watering intervals. The so-called finger test has proven itself. This means that the soil is pressed with the finger at any point and the moisture is determined by feeling and seeing.
The watering quantity is correct if:
- the soil is permanently moist to a depth of about five centimeters
- waterlogging is avoided
- the seed and soil do not dry out
In order for the watering water to penetrate to the required depth and not evaporate again immediately, watering must not be too scarce. For example, the use of lawn sprinklers that apply water to the lawn with moderate intensity but over a long period of time has proven successful. However, since the soil surface dries out even at moderate temperatures and under overcast skies, the individual watering sessions must not be too far apart. The big challenge for you as an amateur gardener is to find the right balance of the optimal amount of water, watering long enough for the necessary depth of moisture, and watering frequently enough to prevent surface drying. Common approaches to watering frequency are as follows:
Spring: daily, in the morning or in the late afternoon after the midday sun has faded.
Summer: early in the morning and late in the evening, both before sunrise and after sunset
Autumn: as in spring
Tip: If watering is done once a day, watering the lawn seeds in the evening is ideal. Then the moisture has enough time to penetrate deeper soil layers without the sun evaporating too much of it again. In addition, during transitional periods, morning dew often provides additional moisture wetting.
How long to water?
After the extent and frequency of watering have been sufficiently clarified, a word should be said about how long a lawn needs to be watered at all. In order for the lawn seeds to actually grow into a true lawn, the area should be kept moist without restriction for at least three to four weeks. Only after the first mowing is the plants so well-developed that they can obtain sufficient moisture from the soil even during dry periods. However, even an established lawn will require occasional watering during periods of extreme drought.
Existing lawns require less water, but still, need to be watered regularly. The water requirement for an established lawn is 2.5 l per day or about 18 l per week.
To check if watering the lawn is necessary, simply walk on the lawn and observe how quickly the lawn grasses rebuild. If this is slow, it is time for watering.