Controlling Weeds in New Pasture

This one can be tricky as many of the herbicides used for general weed control in established pasture are just too tough on new pasture and you risk damaging your new pasture.

Whether grass weeds or broadleaf weeds they can be either annual or perennial. It is really important that you are on top of perennial weed control and you need to have these under control before you sow new pasture. Spray out your old pasture with Rainbow & Brown Glyphosate 360, Glyphosate 540, or Granny. You can also add our Rainbow & Brown Halox 100EC for better grass kill.

When your new pasture is sown you have to give it every chance of success and with the perennial weeds gone you can focus on the annuals that come through which will mostly be growing at the same time, and often at a similar rate, to your new grass so fertilise well.

New pasture responds well to Nitrogen over the first 6-8 months so a couple of applications of Nitrosol Nitrogen Boost liquid nitrogen and / or Nitrosol Oceanic, which has lots of other goodies, will work wonders.

Graze lightly at around the 4-6 week mark for annual, Italian or hybrid grasses and 6-8 weeks for perennial ryegrass. You are aiming just to take the tips off to promote growth. It is not about feeding stock. Graze when conditions are dry and use young stock or just leave cows on for a few hours. Do not overgraze.

As a rule of thumb try and spray weeds before they get to the 4-6 leaf stage. You do really need to have some leaf surface on the weeds to be really effective so sometimes spraying too early is less effective.

This timing is good as it makes identification and spraying easier. These weeds are small so the clover-safe herbicides like Decision are more effective on them. Commonly used are Decision (flumetsulam), MCPB+MCPA, and bentazone. 

If you miss some weeds and these get established, it is not the end of the world, but it is very likely that in order to kill them at this stage your herbicide options are limited to herbicides that are less clover-friendly or will knock your clover around. Things like GrassMate, Triclo, 2,4-D 720 Amine, MCPA750 cover different ranges of weeds and range from minor to severe clover damage so identifying the weeds and selecting the right herbicides is important. Check out our weed files or give us a call or email if unsure.

If you have just a few weeds popping back through, then keep some Buckshot granules on the bike or the Ute and when you spot them just sprinkle some Buckshot granules on them.

So, to summarise:

• Control your perennial weeds in your existing pasture before you think of crop rotation or spraying out.
• Spray out effectively with our glyphosate range but add other herbicides to maximise the effect.
• Glyphosate is ideal as there is no residual activity preventing pasture or clover re-establishment.
• Regularly check your new pasture to identify weeds and keep an eye on the size.
• Fertilise well
• Lightly graze to remove the tips.
• Spray before the weeds get too big but make sure they are big enough to take in the spray effectively.