Tetraploid ryegrass varieties are often marketed as a good alternative for SOS on sports pitches. Generally, tetraploids grow quickly but laboratory research has proven that SOS is of higher quality and that its rate of establishment (at 4°C) is better.
Tetraploid ryegrasses do not match Westerwold ryegrasses when it comes to growth or establishment at low soil temperatures. The varieties which are now available have little advantage over recreational grasses in terms of wear tolerance.
Current varieties of tetraploid grasses are sold as an alternative to SOS for sports fields. They have had some recent success in repairing and overseeding sports fields at different times of the year, especially outside the growing season.
Tetraploids generally grow quickly but do not have the same capacity as SOS to germinate and establish fast at a temperature as low as 4°C. That has been proven in laboratory trials.
Extensive research by organisations such as STRI have proven that tetraploids offer little advantage as a permanent solution. That is due to the poor turf density and wear tolerance.