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Grassland Reseeding

Why Reseed?

Recent Moorepark research shows that old permanent pasture:

  • Produces on average 3 t DM/ha/year less than perennial ryegrass dominated swards
  • It is up to 25 per cent less responsive to available nutrients such as nitrogen than perennial ryegrass dominated swards.

Reseeding will:

  • Increase the overall productivity of the farm (sales, farm output & silage production)
  • Allow higher animal output per hectare relative to permanent pasture
  • Increase grass quality and utilisation
  • Establish uniform clover swards
Eddie Gavin - Reseeding on his farm

Eddie Gavin gives an overview of his farm and farming system and explains the importance of reseeding

The 10 Steps to Reseeding

  1. Identify under-performing paddocks for reseeding
  2. Plan to reseed early
  3. Soil test –Before reseeding
  4. Spray off paddock
  5. Prepare a firm, fine seed bed
  6. Choose the most profitable varieties (Use Pasture Profit Index)
  7. Spread lime and N,P and K
  8. Roll after sowing
  9. Post emergence spray
  10. Graze at a low cover (700kg-1000kgDM/ha)


  • Clover should be considered in all reseeds
  • Clover must be incorporated into reseeds for farmers in Derogation


  • All methods are effective when carried out correctly

Soil Fertility:

  • Soil test, lime and appropriate fertiliser (N, P & K) (2.5 T lime/acre) (3 bags 10-10-20/acre)
  • Lime - Increase seed germination
  • Optimum pH – 6.3, P: Index 3 and K: index 4

Post sowing management: 

  • Ensure seed bed is rolled following seeding
  • +30 Units N/Acre (Weeks 4-5)
  • Post emergence spray - 5-6 weeks after reseeding (best time to control docks)
  • 1st grazing – 700 – 1000 kg DM/ha
  • Graze every 17 – 21 days (1000 – 1400 kg DM/ha)
  • Check for uniform establishment (pests)
  • Avoid silage in first year if possible


The Pasture Profit Index (PPI)

When the decision to reseed is made, the next major decision is selecting the most appropriate grass variety or varieties. The first thing to consider is the primary target use of the field. Is it predominantly grazing or is it generally used as a silage paddock? How much tetraploid should be used?

The Pasture Profit Index is a tool which farmers can use to select the varieties which best meet the needs of the paddock they're reseeding. It is a table of the top varities and they are ranked based on their profit potential for the key traits;

  • Seasonal DM Yield
  • Quality
  • Silage Making
  • Persistency in Sward

Please click Recommended Intermediate and Late Perennial Ryegrass Varieties 2021 (PDF) for a printable version. Guide to reading the table:

  • Variety details: Variety, Ploidy (T= tetraploid; D= diploid), Heading date
  • PPI details (Total €/ha per year): indicates relative profitability difference when compared to the base values.
  • PPI sub-indices: Seasonal DM yield (spring, summer and autumn), Quality (April, May, June and July), Silage (1st and 2nd cut), Persistency.

This indicates the economic merit of each variety within each trait, summed together this provides the overall PPI value. When using the index evaluate varieties across there sub index values and choose the most appropriate for the intended enterprise.

For more info on the PPI please see Pasture Profit Index page.

Using PPI & Reseeding

Watch Michael O'Donovan (Teagasc, Moorepark) talk about using the PPI when reseeding on Tim Crowley's farm, Tim was the 2017 Young Grassland Farmer of the Year.

Explaining the Pasture Profit Index 2021

Pocket Manual for Reseeding

All the information you need on reseeding is in our pocket manual below including;

  • which paddock to reseed
  • when to reseed
  • choosing grass varieties (PPI)
  • soil fertility
  • cultivation methods
  • weed control 
  • grazing management after reseeding.

If there is anything you would like more information on please contact your local Teagasc advisor or if you know somebody who would benefit from the manual let them know where to find it!

Pocket Manual for Reseeding (PDF)


Benefits of reseeding

Before reseeding it is advised to think about what you want from your variety. Pick a variety that is suitable for what you want it for, be it grazing or silage.