How often to spray weeds?

aliasojo

I've just bought a sprayer and a 5l container of concentrated glyphosate weedkiller.

There is a reasonably large hardstanding area where the weeds are breaking though the cracks in the tarmac/gravel and have grown like wildfire round the edges.

I sprayed it all last night...how long should I leave it before spraying again? I'm assuming it will need done more at the start to get things under control?

Davesnave

You don't need to spray again for a few weeks.

It may take up to two weeks for the results of what you've done already to show properly.

Of course in that two weeks another tranche of weeds will start to grow, but you'll be able to see where they are later and target them more effectively.

Leif

As above. It took 2 weeks for weeds in my garden to show some signs of distress i.e. yellowing. Some are more resistant than others.

If the weeds are established perennials you may find the weedkiller does not kill the roots, and they'll pop back up again in a month or two. Some weeds such as bramble seem to shrug off glyphosate, other such as Bird's Foot Trefoil die back then reappear. The weedkiller works best with a decent leaf area, as it is the leaf that absorbs the stuff.

aliasojo

Thanks both, very helpful. :beer: