Weather conditions in August are often ideal for the establishment of new reseeds, however autumn reseeding can face many challenges which are often not experienced in spring. Many of these challenges can be mitigated by following a number of key management practises; starting with an early as possible August sowing date. The ultimate goal when autumn reseeding is to facilitate the best chance of achieving a well-established sward for next spring. The following points will go a long way in helping to accomplish that.
1. Sowing date
Once we approach late August/early September, weather can become more challenging for the establishment of grass seed. The earlier in August grass seed is sown the better chance it has of a successful establishment. A well-established sward is also more capable of competing with weeds. The recommended sowing rate for perennial ryegrass mixtures is 14kg/acre.
Ensure the new sward has adequate nutrition – generally 3 bags of 10:10:20 per acre is advised for soil index 3, but check your soil test results and ensure you remain within your Nitrogen (N) and Phosphorous (P) levels in the nitrates. It is also important to reference your soil sample results for liming requirements as optimising the pH of grassland soils will increase the annual output of grass. Apply the fertiliser after the seed is sown as adequate P and Potassium (K) is essential for root and tiller development of the new plants. Follow with N approximately 3 weeks after sowing, but ensure it is within your allowances and spread before the September deadline.
Pests can be problematic with autumn reseeds, so it is important to ensure all steps are taken to give the new reseed every possible chance. Monitor the new reseed for pests and seek advice if you think you have a problem. Most likely pests are slugs, frit-fly and leatherjackets.
4. Weed Control
Post-emergence weed control is the most vital and cost-effective opportunity you will have for weed control in the new sward. Apply approximately 6 weeks after sowing when weeds are actively growing. Ensure the product label allows use in your timeframe as some new ley sprays are not permitted after the 31st August. Check the label to ensure you are cross compliant and if you have sown clover, use a clover safe spray.
Check the label on your post-emergent weed spray to see when the sward can be grazed. This early grazing is critical to help ensure you have a better tillered and denser sward for the following spring.
Often cows will do a better job than calves, as although they are heavier, they will graze quicker and can be removed from the new reseed much sooner. However, it is important to ensure ground conditions are firm enough to allow so.
6. Choosing the best grass mixtures
When selecting your grazing mixture, focusing on varieties with strong PPI values and high quality are essential to maximise the return on your investment. Choosing varieties with positive values for quality will help ensure you have a palatable mixture, which will support higher animal intakes and animal performance. Varieties with good spring and autumn growth are also desirable to increase grass availability at these key points in your grazing season.
A maximum of 3 to 4 varieties in a mix is the ideal as if you have too many varieties, some will be included at a low rate and the benefit of that variety over an acre would be questionable.
Our Autumn Reseeding Webinar hosted by Dermot Campion from Germinal and Sandra Hayes from Teagasc can be viewed using the link below.