Sports Turf Agronomy Advice - September 2025
After another month of minimal rainfall, conditions are still extremely dry and not ideal for grass growth.
August was generally pleasantly mild, with less extreme heat that we have had in previous months, which has meant that although still dry, there hasn’t been the additional stress of extreme heat and light. It has however been a persistent challenge this season keeping on top of stressed turf due to the low moisture availability.
September typically sees a shift in weather conditions, which become more autumnal. There is usually more moisture around, cooler conditions providing early morning and late evening dew formation. There will be many that are now waiting for a window of opportunity to drill seed into the ground to aid recovery where grass coverage has been lost. Allowing the ground to rewet enough so there is sufficient moisture available for new seed will be crucial for successful overseeding. We will start to experience darker mornings and nights, so the plant will have less light availability for photosynthesis. The turf managers focus is now on recovery but also moisture management in terms of leaf wetness for integrated disease management to minimise any outbreaks.
Looking back at the figures from August, GP decreased from 95% down to 91%, so although this still indicates growth is strong, it shows the start of the coming trend of everything beginning to reduce in terms of growing conditions towards the end of the year. Moisture content is lower than July which has again had an impact on growth due to continued turf stress. Weekly nitrogen requirements are also down slightly from 5.73 to 5.4. September will be a balancing act of managing recovery when areas regain moisture levels against managing moisture to reduce any conditions that would benefit the development of turfgrass diseases. Which will be challenging.
Click here to review weather data in your region for August. To keep up to date with the weather throughout September click here
The forecast for September does look like a continuation of the weather pattern from the end of August. The month starts with dry weather and temperatures remaining around the late teens. Although by week two and three, things have become unsettled with some rainy days. Given the recent conditions this will be most welcomed by turf managers. Towards the end of the month, conditions are predicted to settle again with more dry days. If correct, this may mean we head into October with some moisture back in the ground and still have favourable temperatures, without it being too wet.
Recovery
For anyone without automatic irrigation systems or a means of applying water this is going to be one of the focus points for the next 4 -8 weeks. In reality, there are still areas that have not fully recovered from the winter, where the spring growth was poor on worn, high traffic areas. This has been compounded by the drought conditions we have experienced in most parts of the country since spring.
Getting grass coverage on these areas before conditions become unfavourable for seed germination and establishment is crucial. Areas that do not have good recovery and are left open with bare ground are at higher risk of colonisation from either annual meadow grass and moss. Either is not a good option, although some will take annual meadow grass over bare ground, the issue here is that it will only become a problem later down the line. A weak grass species, given stressful situations will suffer and the ground will revert back to being bare and then it’s back to square one.
Taking the time to select the right cultivars will increase the chances of success with a long-term view. Each site will have species and cultivars that are best suited to that particular growing environment and the seed selected should compliment the existing sward composition, or if the goal is improvement of the existing sward, then selecting the cultivars with the desired characteristics is key.
The BPSB booklet and your regional seed manufacturer can offer great insight into specific seed mixes. There is a great deal of research and development that goes into the balance of seed mixes and your regional advisor can explain the benefits of particular mixes.
Once selected, timing of application in the right conditions to ensure success will be important. The ground is extremely dry currently and will take significant re-wetting before it is in a suitable condition to host seed germination and establishment. Wetting agents may be useful in ensuring this process has a greater success rate. Once in the ground, application of nutrition with a good amount of Phosphorous and biostimulants can increase the rate of establishment to ensure good ground coverage ahead of winter.
Disease
Disease pressure has been relatively moderate throughout August, with some activity but nothing excessive. In September, expect conditions to become more suitable for disease development with the increase in moisture levels in both the soil and on the leaf surface.
When the 3 constituents of the disease triangle combine, and surfaces can become damaged. Because of this, it can be an appropriate time to put in place a preventive disease management plan. This will ideally be an integrated plan which combines a multitude of different approaches in a bid to keep any disease outbreaks to a minimum. This will include:
- Carefully selected nutrition from an appropriate nitrogen source (one that isn’t going to contribute to disease development)
- Preventive fungicide applications
- Non- fungicidal applications, biostimulants, and moisture management, with dew control
These can be utilised in a synergistic approach where each application compliments the next in the effort to minimise disease outbreaks and maximise plant health. When planning management strategies through this period having an overview of all the planned applications allows you to piece together each part of the plan. For example, where the nutrition is coming from (granules vs liquids), how many fungicide applications, what else can be done to supplement these and keep the sward as healthy as possible. All these factors need to be considered and overlayed with the forecasted weather to ascertain the predicted levels of disease pressure, leaf wetness, spray windows etc…Bearing in mind the best plans can be foiled by unpredictable weather patterns.
Pests
Adult crane fly activity typically increases in September and therefore being extra vigilant when on the turf for any activity will help to accurately time Acelepryn applications. The adults commence egg laying almost immediately, with hatching and larvae emergence about two weeks later. You can check reported sightings of crane fly species on the Pest Tracker on the GreenCast website.
To aid effective timing of treatment, ensure the product is in the soil around a month after recording them flying on the wing. Where chemical control is not authorised, entomopahogenic nematodes can be applied with warm soil temperatures and available moisture being ideal conditions to get the best out of an application. The entomopahogenic nematodes swim in the water film on soil particles in their bid to search out a larval host, useful information can be found here.
Tom Wood
B.Sc (Hons) | MBPR | FQA