Overseeding at low temperatures

Sports pitches are intensively used and they can develop bare patches during the winter months. Replacing an entire pitch is often just too expensive. SOS® makes it possible to overseed during the winter. This grass seed germinates quickly, promoting speedy recovery of the sward.

Germination at soil temperatures of 4°C

SOS® makes it possible to overseed during or shortly after the winter. It is unique because it can germinate at a soil temperature as low as 4°C. Speedy germination and regrowth promote speedy recovery: within two to three weeks, you will have a smooth, dense turf once again. Speedy recovery after the winter damage significantly increases the number of playing hours.


Overseeding during the winter months with SOS® results in fewer postponed matches, better football in the penalty box and fewer injuries.

SOS grows where other grasses fail

During autumn, a ryegrass mixture can function perfectly well - if the conditions are right. Nevertheless, that cannot always be said of autumn. Overseeding in autumn has a good chance, despite the uncertain temperatures. Overseeding gives a good head start on possible invasions by weeds and unwanted annual meadow grass, which usually rears its ugly head in early spring.


From November onwards, the growth factors for grass noticeably deteriorate. For example, there is not enough light, the temperatures are too low and there is too much rainfall. This can put too much strain on the grass - resulting in outbreaks of fusarium and leaf spot disease, and poor recovery after playing or damage.


Although ryegrass can continue to grow in a temperate climate during the autumn and winter, it is not ideal to use 100% ryegrass, Lolium perenne, for overseeding. Not to mention a mixture containing smooth-stalked meadow grass, Poa pratensis. Meadow grass is by nature slow growing and it needs light for germination. For both varieties, the chance of success gets smaller as the days get colder and darker.



In practice, many pitches are overseeded using a grass mixture, which germinates at around 10 °C. The problem here is that annual meadow grass germinates as low as 8 °C. Annual meadow grass sprouts very quickly and the overseeded mixture doesn't have a chance. Annual meadow grass is a real nightmare for a field manager. For more information, click here. If you want to beat annual meadow grass, choose SOS® by Barenbrug. SOS® germinates at low soil temperatures, even at 4°C.


SOS® takes on the challenge and, with constant overseeding; annual meadow grass gets little chance to establish. Click here for more information on SOS®. Barenbrug uses the calculation method 'Growing Degree Days.' Growing Degree Days calculates how many days a grass mixture or variety needs for germination to begin. This calculation indicates that SOS® needs fewer degree days than annual meadow grass.


Unfortunately, the calculation also indicates that annual meadow grass does germinate much earlier than ryegrass. Therefore, at low temperatures, SOS® is the ideal overseeding mixture for getting a head start on annual meadow grass.


Annual meadow grass versus SOS

As already mentioned, SOS® germinates at 4°C. Its germination speed beats annual meadow grass, which germinates at a soil temperature of 8 °C. If annual meadow grass were allowed to keep on growing, it would need a lot of light. SOS® needs light, too, but not nearly as much as annual meadow grass.


Both grass varieties score the same in terms of moisture and irrigation. Annual meadow grass and SOS® both need moisture. However, annual meadow grass suffers from stress if there is even a short-term drought. Stress causes annual meadow grass to reproduce very quickly and then it spreads like wildfire. On the other hand, if it gets too wet it soon causes a build-up of thatch. After some time, this thatch layer prevents water from draining away, which can result in the pitch becoming waterlogged. Finally, annual meadow grass needs a great deal of nitrogen, whereas SOS® needs much less.


Click here for more information on Annual meadow grass.

Field top maker

When a field is actually beyond saving, a field top maker may be used. A field top maker is used to aerate a sports pitch or remove unwanted surface matter. While aerating, most of the annual meadow grass is removed because its shallow roots make it easy to pull out of the soil.  It is advisable to overseed with a suitable grass mixture shortly after aerating.


There is also another, more rigorous option - use the field top maker to remove the top soil from the entire field. All of the grass is removed and needs to be disposed of. The next step is to choose the best mixture that will establish a nice, hardwearing sward as soon as possible. Barenbrug's RPR® is a good option.


RPR® germinates very quickly; it has creeping stolons, which form a sort of network across the turf. The plants are as such joined together and that makes the grass extremely strong. Therefore, this grass is very rarely damaged, should that happen, RPR®'s capacity for self-recovery gets to work. RPR® forms such a dense turf that annual meadow grass can hardly take hold.

Constant maintenance

To keep sports pitches in good repair, it is important to sow grass seed continuously. If bare patches appear after a match, overseeding can be carried out straight away to combat annual meadow grass. If you don't do that, there is a big chance that annual meadow grass can establish itself everywhere and take over the sports pitch. Annual meadow grass also poses a problem for golf courses.


SOS® is a good choice for overseeding in the winter months. RPR® is a better option when the weather is warmer. RPR® forms stolons, which create a network of exceptionally strong grass plants. Annual meadow grass may look green and healthy, but it can have nasty side effects, which can even make sports pitch unplayable.


Please click here, if you would like more information about RPR®.