Weed control in a new reseed: Timing is crucial

Tuesday 04.06.2019 , News

Controlling weeds in a young reseed is the best opportunity for long term clean swards. Once established, the root of a dock plant can be in excess of 1 metre deep, making it a very difficult plant to kill. Furthermore, a single dock plant can produce over 60,000 seeds per year, therefore it pays to eliminate them early.

Seedling docks are much easier to eradicate from your sward in the early days compared to established dock plants, and the same can be said for the most common grassland weeds. These include perennial weeds such as docks and thistles, as well as annual weeds like chickweed.

Which weeds should I be concerned about?

Annual weeds such as fumitory, fat hen and deadnettle only live for one year. These weeds should not affect the establishment of the new sward, unless they are present in high numbers – if so, spray them. They are normally removed by grazing, cutting or leaving them to die naturally over the winter.

Perennial weeds such as docks, dandelions, creeping buttercup and creeping thistle should be controlled in a new ley to avoid an increase in plant population down the road. Chickweed is also a problem weed in new reseeds, especially with autumn sowings, or when the grass is slow to establish.

What product should I use?

There are a range of products available and approved for new leys. Product choice is decided by the presence or absence of clover in the new ley. Ensure the product is approved for new leys and seek advice from a qualified advisor. Clover safe sprays suitable for new leys include Legumex DB, Undersown, CloveX and UnderClear. Non-clover safe sprays approved for use in new leys include Hurler, Reaper, Binder and Envy.

Points to note when applying herbicides

  • Ensure the sward is even and growing vigorously. Avoid spraying in very dry or cold conditions.
  • Spray 6-8 weeks after reseeding when there are 3 leaves on the grass and 1 true leaf on the clover. If clover is present, ensure you use a clover safe spray.
  • Apply the herbicide onto small, actively growing weeds (e.g. dock leaf = size of €2 coin).
  • Adhere to advised application rates on the product label and keep water rates high.
  • Always read the label before use.
  • Never fill sprayers from watercourses.
  • Do not spray in windy conditions or when rain is forecasted.
  • Adhere to product label guidelines for timeline between application and grazing.
  • Remember to keep the prescribed cross-compliance records and follow the product label.
  • Only registered professional users can apply professional use herbicides.
  • Discuss with your merchant/advisor if you have any queries

Ask the grass and forage seed experts