Reseeding grassland is a vital practice for farmers aiming to maximise forage production, improve livestock performance and enhance farm profitability. Over time, productive species like perennial ryegrass decline in swards, replaced by less productive weeds and grasses, resulting in lower yields and feed quality. Research shows that reseeded swards can yield 20–40% more grass than older pastures, with much of this extra growth occurring in the critical spring and autumn periods. Improved swards also respond better to fertiliser, offer higher digestibility and protein and support greater milk output or liveweight gain.
Why Autumn Reseeding?
Autumn offers an ideal window for reseeding, typically from mid-August to mid-September. The cooler, moist conditions favour seedling establishment, allowing roots to develop before winter and resulting in vigorous growth the following spring. Autumn reseeds are less likely to suffer from drought and often face fewer weed problems. However, successful reseeding depends on careful planning and attention to detail.
The Critical Role of Soil pH and Fertility
Soil pH is a key factor in reseeding success. The target pH for grassland is 6.3–6.5, which maximises nutrient availability and uptake by the new sward. At lower pH levels, the efficiency of nitrogen, phosphorus, and potassium fertilisers drops dramatically—meaning wasted investment and poorer establishment. Reseeding provides an excellent opportunity to correct soil pH and address underlying fertility or drainage issues.
Correcting pH is most effectively achieved by applying lime. Calciprill, a granular lime produced from pure calcium carbonate in Northern Ireland, is particularly effective for this purpose. Its fine particle size ensures rapid action, and its granulated form makes it easy to spread using standard fertiliser equipment. Just 150kg of Calciprill delivers the same neutralising power as 1,000kg of traditional bulk lime, making it a cost-effective and efficient solution. Calciprill is especially useful in direct drilling systems, where the decay of the old sward can create acidic conditions that hinder seedling establishment.
Steps for a Successful Autumn Reseed
- Field Selection: Prioritise underperforming fields or those with less than 50–60% perennial ryegrass.
- Soil Testing: Conduct a recent soil test to determine pH and nutrient status. Address any fertility or drainage issues before reseeding.
- Spray Off Old Sward: Use glyphosate to remove the existing vegetation and prepare for a clean seedbed.
- Correct pH: Apply Calciprill or other lime products based on soil test recommendations to achieve the target pH.
- Seedbed Preparation: Create a fine, firm seedbed through cultivation or direct drilling.
- Fertiliser Application: Apply nutrients as per soil analysis, ensuring adequate phosphorus, potassium, and nitrogen for establishment.
- Sowing: Select a grass seed mixture suited to your farm’s needs—Fane Valley offers expert advice and tailored mixtures.
- Rolling: Roll the field post-sowing to ensure good seed-to-soil contact.
- Early Grazing: Graze the new sward lightly once seedlings are well-rooted to encourage tillering and sward density.
For reseeding advice, contact your local Fane Valley agronomist or call 028 9261 0485.
