Wet weather over recent weeks has created ideal soil conditions for important autumn over seeding to rejuvenate sports pitches and golf courses. But levels of success could be seriously compromised by strong competition from continuing growth of the existing sward.
An end-of-season application of Primo MAXX, in early to mid-September, will suppress growth of the existing turf, and enables new seedlings to get established more successfully, according to Simon Elsworth of Syngenta.
Mr Elsworth highlights that trials conducted by the STRI on high quality sports turf have shown that a treatment of Primo MAXX five days prior to over seeding can achieve the optimum results in seedling establishment and sward density.
"New seedlings need to establish quickly to build up root and leaf reserves, if they are to survive the rigours of winter weather and recover from the wear and tear of heavy use," he advises. "Primo MAXX treatment gave faster results in achieving turf coverage and density, which is so essential to get sports surfaces back in playing condition quicker."
Trial results showed areas treated before sowing reached optimum sward density within 21 days of sowing, when untreated areas or areas treated after sowing had still only reached a reduced level of cover. Five weeks after sowing, turf cover on the Primo MAXX treated areas was improved by 40%, compared to areas without the treatment that were only 6% better than areas with no seeding at all.
"With light levels falling rapidly into the autumn, suppression of the existing sward ensures adequate light will reach the new seedlings. This will encourage greater tillering and lateral growth to improve turf density," adds Mr Elsworth.
Limiting vertical growth of existing turf will also reduce the frequency of mowing and the resulting stress on the new seedlings. Mower operators are advised to raise the height of cut for the first five cuts after seedlings emerge, then gradually reduce to the required winter mowing height.
Mr Elsworth also advocates Primo MAXX application on previously sown turf, four to six weeks after seedling emergence, through to the end of September or mid-October where turf is still actively growing. "This will encourage new seedlings to produce more roots and lateral growth - filling gaps and creating a denser sward. The MAXX formulation is very safe for young seedlings, with no negative effects on germination or plant development."
Tackling seedling diseases
Mr Elsworth warns that seedling diseases can quickly wipe out delicate turf plants before they can establish. Too high a seed rate, surface moisture and incorrect nutrition will all encourage seedling diseases. Bent grass and fescues are most susceptible to seedling disease causing post-emergence damping off.
"Fusarium pressure is rising in the cooling conditions, along with a legacy of Rust and Anthracnose from the summer. An application of the fungicide Heritage can protect new seedlings against a broad-spectrum of diseases that cause damping off, including Pythium, Microdochium and Rhizoctonia."