The overseeding options in 2019

By Alistair March 22, 2019 07:43 Updated

Jayne Leyland, seed and linemarking product manager for Rigby Taylor, discusses the 2019 options for overseeding and the benefits, together with advances in grass seed treatment technology.

Fescue and bent grass mixtures such as R1, R105 and R117 have long been the traditional choice for overseeding golf greens. But let’s explore some progressive options which, for the majority of courses prove to be more sustainable options to bent and fescues in challenging conditions.

Bent / poa greens

From the result of generations of grass breeding, the mixture R Duo offers superior characteristics for golf greens in comparison with poa annua (annual meadowgrass). The blend of Two Putt Poa annua var. reptans together with Egmont browntop bent produces a mid-green, fine leafed sward with good winter colour and early spring green-up. The perfect blend for improving poa dominant and poa / bent greens, R Duo is faster establishing than traditional bent grass blends, especially in cooler conditions. High tiller density and stoloniferous growth helps compete against poa annua, withstanding close mowing down to 2.5mm in the active growing season. Tolerant of shade and cold, wet soils, R Duo is ideal for repairing poa / bent greens. A wide pH range and increased tolerance to dollar spot and anthracnose diseases, R Duo produces a true, consistent putting surface under good management practices.

Faster and stronger

Intense wear and increasing disease pressure makes fast establishing grasses a vital part of golf greens’ maintenance. Where traditional bents and fescues struggle to establish and survive, cultivars of ultra-fine, dwarf perennial ryegrasses especially bred for golf course applications really deliver. Tolerant of close mowing and with very fast establishment, R9 combines ultra-fine leaf, high shoot density, clean cut, fast recovery from close mowing and exceptional tolerance to red thread disease. Although not usually fatal to the grass plant, red thread is increasingly aggressive and unsightly, weakening the plant and making it increasingly susceptible to attack from more lethal turf diseases.

Long term benefits

Choosing mixtures with increased disease tolerance is becoming ever critical. So too is fast establishment which not only brings the surface back into play faster but also supports plant health in the longer term. R Range mixtures treated with Germin-8T really provide added value.

In the short term the penetrating surfactant, sugars and micro nutrients help the plants establish faster whilst the benefits of mycorrhizal fungi and trichoderma atroviride deliver longer term, symbiotic health benefits of nutrient assimilation and disease protection to the established plant. Only two per cent by weight, Germin-8T liquid seed treatment means you can sow at the usual recommended sowing rate, delivering genuine benefits without additional cost.

The summer of 2018 was a firm reminder, if one were needed, of how the changes in climatic conditions are dramatically challenging and shaping our environment.

And, if the damage caused by the heat and drought was not enough, the revocation of recognised chemical controls for turf grass diseases increases the pressures. Fortunately, help is at hand with the latest grass seed technologies offering sustainable overseeding solutions to help maintain true, consistent putting surfaces.

In with the extraordinary

One exciting grass seed technology is the liquid seed treatment Gemin-8T, an innovation that has provided users of the Rigby Taylor ‘R’ range of seed mixtures with improved germination and enhanced seedling establishment.

Pre-applied to each individual grass seed, Germin-8T contains a speciality surfactant that activates on contact with soil moisture. Adequate moisture in the soil profile is essential to trigger germination so the speciality penetrating surfactant helps lower surface tension to aid faster water penetration through the seeds natural waxy seed coat (pericarp) into the seeds endosperm, speeding up germination. During this early emergence phase each seedling has immediate access to Germin-8T’s highly beneficial package of targeted nutrients, biostimulants and micronised mycorrhizal fungi that together aid early establishment, improved root mass development and accelerated leaf extension.

Germin-8T treated seed allowing early availability of nutrients to the emerging roots

Such accelerated establishment allows the young plant root system to benefit from the micronised mycorrhizal fungi, which delivers long-term symbiotic benefits to plant health.

The ‘T’ in the product name identifies that this advanced formulation now contains trichoderma atroviride, which is a filamentous soil fungi that forms a mutual endophytic, beneficial relationship with grass plants and delivers increased tolerance to leaf spot, pythium and also to rhizoctonia turf grass diseases.

Seed establishment comparison – 10 days after treatment at 8ºC. Left untreated; right Germin-8T treated

Germin-8T provides significant benefits, not least in cold, wet conditions when the emerging seedlings are most vulnerable; this leads to higher plant survival rates following renovation.

As a liquid treatment, Germin-8T adds just a maximum two per cent increase in bag weight so there is no requirement to increase seed sowing rates above those recommended. Unlike powder coatings, that increase the weight of the bag and seed sowing rates, there is no risk of broken particles or dust. Germin-8T is available as standard on all of the ‘R’ range of Rigby Taylor grass seeds.