If you’re looking to refresh your pastures without taking ground out for a full reseed, have you considered rejuvenating your existing swards? Sward rejuvenation, by overseeding or stitching-in, can be an option to improve underperforming swards with minimum time out of production. It can be a flexible, cost-effective way to gain two or three more years out of a sward before a full reseed is required.
When used selectively, sward rejuvenation can enhance pastures which are past their best but have not deteriorated too far and still have at least 50% perennial ryegrass. It can also be useful where ground is difficult to fully reseed due to it being sloped or stony.
For pastures where broadleaf weeds, such as docks, thistles and nettles, are a problem, these are best controlled before overseeding in order to open out the sward. However, if weed grasses are the problem then a full reseed may be a more cost-effective solution.
The ideal conditions for rejuvenating swards are warm and damp. Overseeding is less likely to be successful if followed by dry conditions, so try to pick a time when rain is forecast with no risk of drought or extended dry spells.
Just as with a full reseed, pay close attention to soil conditions, such as fertility, structure and nutrient status, before starting. Carry out a soil test and examination of your soil so you can correct any issues in advance. Spread 1.5-2 bags/acre of 10:10:20 as P and K are important for root and tiller development. Correcting any issues is vital as they could be the reason why an existing sward is performing poorly.
Before rejuvenating make sure the pasture is either grazed down as tightly as possible or take a heavy cut of silage to reduce competition between the new seedlings and the existing sward.
Look to sow at a seed rate of 8kg/acre and consider using tetraploids as part of your mixture. Their larger seeds make them better able to compete with the old sward.
Use the best method for your ground
Sward rejuvenation can be achieved by either stitching-in the seeds or scratching the surface with tines. A few runs with the tines to pull out grass thatch and loosen the soil is advised, before spreading seed on the loosened soil. Whichever method you use, seeds must make good contact with the soil or they’ll struggle to germinate, so soil must be visible prior to sowing. Use a sowing depth of approximately 10mm and if conditions are suitable, roll after sowing for good soil-to-seed contact.
After sowing, monitor closely and check the seedlings have established. Once they have reached the three-leaf stage, are beginning to tiller and don’t ‘pull out’, the sward should be lightly grazed, to aid tillering of the new grass.
Finally, don’t expect to see major differences within the pasture immediately – it takes time for the new seeds to establish.