In case you hadn't noticed it, given the exceptionally mild conditions we are currently experiencing it just about winter! Yes .......this is hard to fathom when ambient daytime temperatures are still 21 - 23oC and we're still applying sunscreen on a daily basis! However, the late summer conditions refuse to budge and we're still shifting irrigators daily on the turf farm which is bizarre given that in the previous 30 years of turf production Finelawn has never previously operated the irrigation system in the month of May. Surely this has to be a "wake up" call for all those climate change skeptics! However, the sun follows its annual pattern regardless of the daily weather pattern and consequently daylight hours are diminishing rapidly which means that plant metabolism is slowing down appreciably. This is more noticeable in warm season grasses such as couch and kikuyu rather than the traditional cool season grasses. So ...what are the priority tasks that need to occur at this time of the year;
- Some over-sowing can still occur as the ground temperatures are still warm enough to trigger rapid
- germination. Please be advised that Tall Fescue in particular will become increasingly more difficult to germinate as ground temperatures decrease.
- It is really important to manage water applications very carefully at this time of the year. Typically, irrigation systems are well and truly turned off by now however, soil water is still limiting meaning that irrigation is still a necessity in some areas. The key is not to overwater as it is important to ensure that the soil is not overly wet or saturated going into winter as this hinders winter growth rates and can create further problems.
- Mowing management is still important in late autumn particularly if growth rates are high. I recommend to continue with a short mowing interval until these growth rates decline.
- If the lawn is being mown more regularly then it will be important to replace the nutrients lost and removed as clippings. Therefore, this is an important time to maintain fertility levels particularly both the nutrients potassium and nitrogen which are more mobile than either sulphur or phosphate.
- Warm season grasses such as couch and kikuyu will respond very well to light applications of gibberellic acid over the cooler autumn months. They will also retain their colour and look significantly more attractive if this is accompanied by regular nitrogen treatments. Note that gibberellins are naturally occurring plant growth hormones that act to increase growth by increasing cell elongation.
- Autumn rains normally bring a flush of unwanted broadleaf weeds. These should be controlled now so that turfgrasses have ample opportunity to re-colonise these areas before winter. If this treatment is delayed it can lead to a proliferation of poa annua later in winter. For cool season grasses common treatments include products that contain 2,4 D & dicamba (sold as Banvine) dicamba, MCPA & mecaprop (sold as Broadsword) or a combination of Picloram and Triclopyr (sold as Triumph, Victory, Brushkiller). Pease note that for warm season lawns that are comprised of couchgrass, seashore paspalum or kikuyu these latter products cannot be used as they will cause significant damage to these lawn species.