It’s always been marketed as being non-residual, but studies published last year suggested that repeated use could lead to a build up of residues in the soil. I’d still say it’s perfectly safe to use as a one off ground clearance spray though. There’s also one marketed as Deep Root or Root Out which breaks down into a fertilizer after a few weeks. The most efficient option almost always is to dig out the weeds, roots and all. The problems come when, like mine, your plot has both bindweed and horse tail. Bindweed being harder to eradicate using glyphosate (roundup, tumbleweed etc) because the top growth scorches before the weedkiller can be transported to the roots, and horse tail has a waxy coating which prevents the weedkiller getting into the plant. Tricks of the trade with weedkillers: 1. Only use them when the weeds are actively growing. Spraying in the middle of winter is pointless. (I know it’s obvious, but you’d be surprised.) 2. Use a sprayer on a calm day and only allow a fine spray to go on the leaves, if you soak them it just runs off and is much less effective. 3. Add a few drops of washing up liquid to the mix. This helps the weedkiller to stick to the leaves. 4. If you do have horse tail, mix your glyphosate at the strongest dose recommended, add the washing up liquid, and stamp on the weeds before spraying, as this damages the waxy coating covering the leaves._________________
