Status: 08/02/2023 1:34 p.m
For months the lawn was tended and cared for. But suddenly mushrooms shoot out of the grass. Brown spots can also be caused by fungi. What steps do you take to get rid of them?
You can see some mushrooms in the lawn immediately, others only show up as brown, bare spots. They can drive some garden friends to despair and cloud the joy of a well-kept lawn at home. There is a remedy: fungi only spread under certain conditions – and sometimes they are an indication that something is missing in the lawn.
When mushrooms grow in circles: witch rings
The infructescence of the mushrooms can grow out of the lawn almost overnight. They sprout out of the green mostly in small groups, sometimes also in a circle in so-called witch rings. The fungal network, the mycelium, which is sometimes quite large, lies underground and cannot be seen at all. Poisonous fertilizers are often found in the lawn, but various types of swindlers or mushroom relatives can also be found in the lawn.
Where do mushrooms come from?
Moisture promotes fungal growth.
Mushrooms need moisture. Therefore, they sprout preferably from late summer when there is waterlogging after heavy rainfall and in the shade of bushes or trees. They do not do well on permeable, nutrient-rich garden soil. Tiny fungal spores are often blown onto the lawn. If they find good conditions there, they grow quickly. The spores also exist in dead wood that may have gotten onto the lawn with compost or plant substrate. Stumps of sawed-off trees at the edge of the lawn provide a perfect breeding ground for fungi.
We humans also contribute to the spread of fungi: once a fungus is in the lawn, fungal spores can cling to shoes and the blades of the lawnmower – and thus spread further.
What to do about fungi in the lawn?
The visible fruiting bodies of fungi in the lawn are basically more of an optical problem that will be resolved when the grass dries out. However, if you want to get rid of the uninvited guests immediately, you should remove them carefully so as not to spread spores. Otherwise the number of fungi will continue to increase.
The individual mushrooms must be plucked off with the stalk, as close to the ground as possible. It is more complex but more effective to cut them out generously. However, this creates unsightly holes in the lawn. Do not dispose of the removed mushrooms in the compost, but in the household waste. If you mow the mushrooms with the lawnmower, the spores are spread further.
Stress fungi like Pythium: Brown spots in the lawn
If brown patches develop in the lawn over the course of the summer and continue to spread, a so-called stress fungus – for example Pythium – can be the cause. This fungus, which can cause root rot, is promoted by high temperatures, soil compaction, nitrogen and potassium deficiencies and too high a pH value. In contrast, mushrooms with fruiting bodies, such as the witch ring, grow on more acidic soil.
Solution: Improve soil quality and strengthen lawns
Reason for patches becoming bald: a stress fungus.
With all fungi, finding out the source of the problem and improving the quality of the soil will help. A soil analysis can provide information on whether the soil is lacking in nutrients and what the pH value is. A value between 5.5 and 6.5 is aimed for. If the pH is lower, the soil is too acidic. Applying lawn lime makes the soil more basic. However, too much liming can result in a pH that is too high, making nutrients unavailable to the lawn. Based on the results of the soil analysis, the soil and lawn can be treated in a targeted manner, for example with an appropriate soil activator or mineral fertilizer.
Prevention in good time through lawn care
A strong lawn is less susceptible to fungi. If you fertilize, cut and scarify it regularly, you can effectively prevent it. Fungi like to settle on so-called lawn thatch, the remains of mown grass. If fungi keep appearing in the lawn, it is advisable to remove the thatch. If the soil tends to become waterlogged, sand can be worked in after scarifying.
Further information
When mushrooms grow in a circle, it’s often a witch’s ring. If left untreated, the lawn can therefore dry out. more
An optimally maintained lawn is green, dense and lush. In order for the grass to grow optimally, it needs regular care. more
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Garden Docs | 09/11/2021 | 5:35 p.m