Most of the causes of brown patches in newly laid turf can be easily corrected. If the turf has wilted or begun to discolour in places, water is the answer – newly laid turf requires regular watering until the roots become established. In the first week after the grass is laid, you will need to water up to four times a day, depending on the weather conditions, long enough for the water to penetrate about 15cm into the soil. Aim to keep the grass consistently moist. On the second week, you can reduce the watering time to once a day and on the third week to every second day.
After four weeks, the roots should be well established and you can further reduce the watering to once or twice a week soaking the grass to a depth of around 30cm into the soil. Inserting a screwdriver into the lawn should give you a fairly accurate idea of the depth of moisture penetration.
Contact With the Soil
If there is any soil settlement after the turf is laid, air pockets may have formed between turf and soil preventing the roots from taking up water. Lift the turf back from the browned areas and fill with new soil, then press the turf back firmly ensuring that good contact is made then water the area thoroughly. Once the roots establish properly, you should soon see new growth.
Compacted Soil
Compaction of the soil causes the water to run away from the root area of the turf and could be another cause of browning. This is why tilling the area before laying the turf is so important. Where the turf is showing signs of dying, lift it back and aerate the soil underneath by pushing holes into the soil with a screwdriver or something similar. This will ensure that the water soaks in. Replace the turf, press it down firmly, and once again water the area thoroughly.
Premature Fertilisation
If you fertilise the turf too soon, the shallow root system will not be able to absorb the nutrients. Nitrogen leaching into the soil burns the grass and causes browning. Wait for at least six weeks before applying fertiliser to the turf. To repair the browned areas, water thoroughly to dilute the nitrogen levels in the soil and prevent further damage to the new growth.
Diagnosing Problems with Established Lawns
Browning of established lawns may result from a number of factors. Many types of turf will naturally become dormant during winter. Don’t fertilise the grass during periods of drought or when it is already showing signs of stress. Spring or Autumn is the best time to fertilise.
Water your lawn in the early morning – late afternoon or evening watering may cause fungal diseases.
In Spring when the first rains fall, aerate the drier areas of your lawn and add a light amount of seed to those dry areas when you top-dress.
Raise your mowing height to 8cm or above during the hot summer months, the taller grass will reduce water loss from evaporation.
If all else fails, get a soil test done to determine what changes may be needed to get your lawn into tip-top shape.