Dry Patch
Localised 'dry patch' on a golf course
*The above Lawn Care Products are available in the Lawnsmith Shop and discussed below:
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Strictly speaking grass or turf ‘dry patch’ is neither a disease nor a pest but more a ‘condition’ of the soil. Dry patch is where the soil has become water repellent and if a sample of soil is taken when the condition is obvious you will find it is snuff dry even after heavy rainfall. It may also have a musty smell and contain white specks of fungal growth similar to those in Type 1 fairy rings.
This water repellence causes a patchy network of drying brown grass amongst an otherwise green and healthy lawn. It is often associated with compaction and heavy thatch layers particularly in older turf or turf on sandy soils. If the problem is particularly severe and the compaction goes deeper than a few inches you will need to replace the lawn to get rid of it.
If, on the other hand, the lawn is not ancient, and the drying not too severe a plan of renovation and wetting could be attempted with good results.
Remedy
Ensure thatch is less than ½”. If it is more then it must be reduced. However, if you scarify you may need to over seed afterwards. This could be a problem on soil that is water repellent so if you do need to scarify I would recommend a deep scarify in the spring before the soil starts drying out during the warmer drier months. See Raking & Scarifying.
Next, the affected areas of lawn will definitely need aerating to allow water to penetrate. I would use a hollow tine fork aerator* to open the turf up AND relieve compaction. If you have machinery, a lawn aerator* or sandals* you should spike the lawn afterwards as well. See Lawn Aeration & Equipment. It should be noted that hollow tining in particular will increase drying of the lawn surface so be prepared to water if the weather is dry.
The penultimate step is to apply what is known as a ‘Wetting Agent’. Though this does not cure the water repellent nature of the soil it will enable it to stay wet if water is applied. You will need to apply wetting agent* such as Lawnsmith® MAXIMISE 3 to 4 times throughout the summer to maintain water penetration.
Finally, good lawn care practices will continue to make improvements so keep the mowing on the high side to retain moisture, ensure a fertiliser containing potassium is used spring and or autumn to help the grass plants moisture control mechanisms.
You should also be aware that dry patch will have taken several years to develop and is not likely to be cured by this treatment. Therefore, you may well need to re-apply wetting agent plus spiking throughout the late spring and summer of the following year and then periodically as required.
