6.2 Turf problems and controls
1 Weed control
The majority of turfgrass weeds, where still present in unacceptable numbers after routine maintenance practices have been carried out in helping to reduce weed content, will usually be controlled and reduced to acceptable numbers by either one or two applications of a suitable selective herbicide.
Key practices that can be undertaken to help reduce the potential for weed colonisation include:
- Managing usage levels to reduce unacceptable wear and tear.
- Maintain a dense sward by providing appropriate - neither too much nor too little - fertiliser inputs.
- Maintain good root growth and density by correct aeration and decompaction activities, along with limiting machinery usage when moist to wet soil conditions increase the likelihood of smearing and compaction.
- Mow at a suitable height - neither too low, nor too high - to encourage a dense grass sward.
- Mechanical scarification and metal tine raking to reduce and weaken creeping weeds. Also reduce thatch build-up as this will provide a blanket for pest grubs and encourage bird and badger activity in pecking or digging for grubs. Do not scarify too severely, especially when grass growth cannot recover quickly, otherwise thin and bare areas will be exposed for long periods, with this being an ideal opportunity for weed invasion.
- Overseed at times when germination and establishment can be rapid.
- Box off clippings when weed seed spread is potentially high, although this may be impractical if suitable mowing machinery is not available. Boxing off clippings at times of high earthworm casting activity will also reduce a food source for them.
- Water a pitch appropriately to encourage deeper rooting of grasses. Do not overwater.
- Drag brush to remove dew early in the morning, to reduce moist conditions which can contribute to disease attack, and subsequent creation of thin and bare areas in which weeds can colonise.
- Top-dress and work in well so as not to smother existing grass. Do not leave large thin or bare area in which weeds can readily colonise.
- Use sand or sandy top-dressings with a pH that is optimal for grass development.
- Adjust soil pH, or at least the surface layer, to better suit strong grass growth and to reduce the casting potential of earthworms.
- Where weeds are few then remove these by hand to reduce their spread. Doing this on a very regular basis over defined areas of a pitch can see the entire pitch covered over a short period of time.