Overseeding is a remarkably simple and effective way to rejuvenate old or damaged grass leys without the cost of a complete reseed. You can achieve increases in yield and quality without ploughing and the time spent out of production can be reduced.
Be selective
Careful consideration needs to be given to location when choosing where to overseed. choose pastures that have not yet deteriorated too far and still have at least 50% perennial ryegrasses.
“Timing is imperative” and the main aim is to minimise competition from the existing sward. Good seed-to-soil contact is vital when overseeding, and old or tired leys need to be grazed down tight or ideally overseed after a heavy silage cut when the bottom of the sward is more open and exposed. The best time to overseed is early spring when the soils start to warm, or late summer when the existing grasses are not growing as vigorously as they will be in May and June.
Preparation
A soil test well in advance of overseeding will help you address any nutrient deficiencies beforehand. For optimum sward performance P and K indices of 2 and a pH between 6 – 6.5. It`s important to avoid applying any form of Nitrogen for at least 4 weeks to give the new seedlings time to get up and away without them being outcompeted by existing species.
Remove all existing grass by cutting or tight grazing. Modern-day drills are far better at putting the seed in the right spot rather than relying on harrows to whittle the seed down to the soil but any cultivations you do before drilling will improve seed-to-soil contact. It is then important to tightly roll the field to get as much seed-to-soil contact as possible. Rolling will also conserve moisture and flatten any stones and molehills for silage ground.
Tetraploid Ryegrasses are recommended as they are larger in seed size than Diploids and are used because of their strong, competitive growth habits, also they are thought to have a higher drought tolerance compared to Diploids.
Choose the appropriate Wynnstay overseeding grass seed mixture by speaking to a Wynnstay specialist for advice on which mixture suits your needs.
A sowing rate of 10kg/acre works best, and as previously said “Timing is imperative” … A regular supply of moisture is required and be careful not to drill the seed too deep.
Aftercare
You should leave the pasture for 5–6 weeks after sowing and then lightly graze. (Make sure the root system is strong enough to withstand grazing, especially sheep, and that the animals are not pulling up the leaf blade and the root from the ground).
