If planning to reseed this year aim to have it completed by mid-August, writes CAFRE’s Nigel Gould.
This ensures the best chance of success and may allow at least one grazing pre-winter. It will also hopefully allow a post-emergence spray for weed control five to six weeks post-sowing.
Targeting weeds at this early stage before significant root development occurs increases the rate of success.
To achieve a good reseed, it is important soil pH, phosphorus (P) and potassium (K) are at optimum levels.
Target a pH of 6.3, P index of 2+ and K index of 2-. Ensure appropriate levels of P and K are applied. For example, for a soil with P and K indices of 2+ and 2- the recommended application levels of P and K are 50 and 60 kg per hectare, respectively.
Sustaining the sward
An appropriate fertiliser and liming strategy for the established sward is vital in sustaining the sward and minimising the re-occurrence of weeds and less productive grass species.
Decide on a cultivation technique that best suits the type of land. Conventional ploughing is often the best however, where soil is shallow and stoney a min-till approach is more appropriate.
The more common form of min-till involves discing (two to three passes in alternate directions) and/or harrowing, followed by sowing the seed.
It is important to graze or mow/top tightly to minimise the amount of thrash in the sward. Direct drilling into an existing sward is also an option. This usually involves dropping the seed into a shallow channel created by a disc.
The aim when direct drilling is to minimise competition from the existing sward. For this reason, direct drilling straight after silage harvest or after the sward is tightly grazed will maximise success rate.
Ploughing, where possible, will act as a remedy for compaction and should also help with drainage.
Managing spring reseeds
Continue to monitor new spring reseeds and ideally graze down tight to promote tillering; this will also help clover to establish, if sown.
Where a post-emergence spray has not been applied, weeds will tend to go to seed at this time of year.
If this is the case, mow off this material and apply spray to the regrowth. It is important to kill these weeds now before their root systems have a chance to fully develop.