If the lawn suddenly shows brown spots, this shortcoming affects the overall appearance of the garden. Since the damage can be traced back to the most varied of triggers, the hobby gardener cannot avoid doing a thorough cause research. The following overview aims to make a contribution to quickly tracking down the problem and eliminating it.
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If a gardener sees brown patches in the lawn in summer, the first thoughts turn to the subject of drought. Blazing sunshine all day long, combined with a lack of water, can certainly be responsible for the damage. The following tips on lawn care help ensure that things don’t get that far in the first place or which first aid measures are advisable:
- Mow the lawn to a height of 2 cm to 4 cm.
- Do not mow in direct sunshine.
- Thoroughly aerate the lawn with the scarifier.
- Scarify lengthways and crossways to the mowing direction.
- Sweep away all residues with the rake.
- Apply lawn fertilizer and wait 1 to 2 days.
- Spread new lawn seeds with the spreader.
- Work the overseeding into the soil with the rake.
- The seeds are light germs, so they must still be visible.
- Then water thoroughly for a maximum of 2 hours.
- There must be no puddles.
- Waterlogging causes brown spots as well as dryness.
- Once growth begins, mowing takes place weekly.
- Do not mow less than 2 cm.
- Water every 2 days in dry periods.
- Occasionally ventilate the lawn with an aerator.
Regular mowing is of the utmost importance for a consistently green lawn without brown spots. If the grass becomes too long, the tips are green; in the lower part, however, the stalks turn brown because they rot. Experience has shown that if you only use the lawnmower now and then, you will radically cut the grass that is too tall. The result is unsightly brown spots and gaps, and there is even a risk that the lawn will die off completely. The ideal height for a sports lawn is 3 cm to 4 cm. An ornamental lawn thrives best when the stalks are between 2 cm and 4 cm high. Incidentally, investing in an aerator is not absolutely necessary, because the device can be borrowed from numerous hardware stores for little money.
Turf for quick repairs
If the brown spots are due to mistakes in lawn care and only appear in isolated places, the rather time-consuming work around reseeding is not absolutely necessary. The diseased pieces are dug out rectangularly with the spade and replaced with turf. Rolled lawns can be bought by the meter in every well-run garden center or hardware store. This will fill the resulting hole, which should be about 3 cm deeper than the surrounding area, with healthy lawn.
Fight fungi in the lawn
If mistakes in the care of the lawn can be ruled out as the cause of the brown spots, it can be assumed that the area is infected by a fungus. Since a large number of types of fungus are possible, it is important to recognize the damage and to act accordingly.
Snow mold (Fusarium nivale) and typhula rot (Typhula incarnata)
If the lawn lies under a blanket of snow for a long time at temperatures of 0 ° to 8 ° Celsius, there is a risk of snow mold and typhula rot. Round spots form, which at first appear greyish-white to pink in color and later turn brownish. With regard to prevention and control, the following measures are recommended:
- Avoid waterlogging through regular ventilation.
- Scarify every year.
- Always sweep away clippings and leaves.
- Do not use fertilizers with a high nitrogen content.
- Maintain pH at 6.0 on sandy soils.
- Lawn on clay soil has an ideal pH value of 6.5.
Since effective fungicides are currently not approved for use in the home garden, a lot of patience is required when removing snow mold. If you follow the tips mentioned, you will get rid of the fungal infestation in the long run, so that the brown spots in the lawn will disappear.
Brown Patch (Rhizoctonia solani) und Yellow Patch (Rhizoctonia cerealis)
If summer is just around the corner without the snow mold on the lawn in winter, there is no reason to breathe a sigh of relief, because two summer mushrooms are now lurking to make life difficult for gardening enthusiasts. Rhizoctonia solani loves warmth and causes mischief at temperatures between 25 ° and 30 ° Celsius by defacing the lawn with light brown to reddish spots. In the cooler early summer, this is done by the fungus Rhizoctonia cerealis, which can be recognized by the yellow-brown damaged areas. Since both mushrooms prefer a moist warmth, the hobby gardener needs a sure instinct when watering. On the one hand, the lawn needs sufficient water so that it does not dry out. If, on the other hand, it is irrigated too much, this creates the optimal conditions for the yellow and brown fungal infections:
- Water well dosed.
- Ventilate the lawn regularly.
- Now and then sand the surface.
- Use means for grass vitalization.
- Do not give N-straight fertilizers (nitrogen).
To combat such a fungal infection, fungicides for private use have not yet been available either. If the lawn is infested, it is advisable to consult the plant protection database of the Federal Office for Consumer Protection and Food Safety, as this area is updated almost daily.
Witch rings (Marasmius oreades and others)
The majority of fungal diseases that can occur in lawns are linked to certain climatic conditions. In contrast, the Hexenring occur all year round. The experts distinguish between 3 types of infection; However, these show up in a largely uniform pattern of damage. Dark green rings form in the lawn, inside the grass of which the grass turns brown and then dies. In the fight against the witch rings, careful care makes a valuable contribution; however, it may be necessary to loosen up the entire area with the digging fork. Then it is watered and in the following period the fertilizer dose is increased slightly. In the worst case, a widespread appearance of witch rings requires a radical soil replacement:
- Dig out the earth at least 30 cm beyond the ring.
- Fill each hole with a substrate made of seeds, granules and fertilizer.
- Alternatively, repair the excavated areas with turf.
A balanced supply of nutrients will ensure that no more witch rings show up in the long run. The application of long-term fertilizers of Substral or Compo are indispensable in spring and autumn. The experienced hobby gardener makes sure that the fertilization in autumn is not too nitrogen-focused, because this measure leads to soft blades of grass, which increases the risk of fungal attack. A strengthening lawn fertilizer with a high proportion of potassium is more suitable.
If unsightly brown spots appear on the lawn, this is not necessarily due to fungal infections or neglect in maintenance. Various pests also belong to the group of suspects.
- Garden beetle
- May and June beetles
In particular, it is the larvae of these insects that cause the obvious damage to the lawn through their voraciousness. But that’s not all, they attract birds, foxes or wild boars, which are in search of white grubs and give the grass area the rest. In addition to revitalizing lawn care, the troubled hobby gardener receives a biological control agent from Mother Nature in this case. These are nematodes, tiny nematodes of the genus Heterorhabditis (HM nematodes). These are dissolved in water and applied to the infested lawn with a watering can or sprayer. There they immediately go in search of the larvae and finish them off. Nematodes are available from specialist retailers and online shops.
- The type of pest is precisely defined:
- The right type of nematode is used.
- The maximum retention time is taken into account.
- The lawn is sufficiently moist.
- No puddles form because nematodes are non-swimmers.
- There is no direct sunlight.
- The dosage is adhered to according to the instructions.
- The lawn is kept permanently moist for 2 weeks.
Experience has shown that the damage threshold is 50 to 100 larvae per square meter of lawn. Depending on the extent of the pest occurrence, it may be necessary to use the nematodes several times.
Dog urine causes brown spots on lawns
If the research into the causes has not yet achieved convincing results, it can be assumed that the brown spots are caused by dog urine on the lawn. In principle, this legacy left behind by the four-legged friend acts like a natural fertilizer. Therefore, after urinating for the first time, the lawn grows more intensely, with the result that the surface becomes unevenly green. The fact that the unwanted brown spots later develop from this is due to the instinctive behavior of the dogs, because they prefer to go exactly where other dogs have already lifted their legs. The result is over-fertilized areas that slowly turn brown. This is how the damaged areas can be prevented:
- Immediately pour plenty of water on the spot.
- The urine will spread and will not attract other dogs.
- Always water dark green spots in the lawn.
- Apply dog repellent to the area.
If it is a fenced lawn on which only your own dog romps, the environmentally conscious gardening fan gives him the dog rocks from Australia in his drinking water. The stones do not contain any chemical components, but reduce the nitrate in dog urine. This agent is completely harmless to the animal, but the lawn carpet is spared from brown stains from now on.
If the lawn loses its carpet-like uniformity due to yellow and brown spots, the first step in combating it is to investigate the cause in detail. Care errors, fungal diseases and pests are among the most common explanations for the defacement of the grass surface. In contrast to commercial operations, hobby gardeners have so far been denied access to effective fungicides. However, those who approach the matter with a lot of patience will ultimately be rewarded with a lush green, even lawn.