Spring spraying is all about getting on top of weeds early – but if your water quality isn’t right, your herbicide may never reach its full potential. Hard water can tie up glyphosate and other systemic actives before they even hit the leaf, reducing uptake and slowing control. The result? Poorer performance, wasted product, and the risk of going back in again with the sprayer - wasting time, money and increasing the risk of resistance.
Here’s what you need to know to protect every litre in the tank this spring.
Hard water contains calcium, iron, and magnesium ions that bind to glyphosate molecules, forming inactive complexes. Once bound, glyphosate is far less available for plant uptake – reducing efficacy and slowing weed control.
Yes. Isopropylamine, potassium, ammonium – all glyphosate salts are susceptible. The issue isn’t the formulation, it’s the chemistry. Without conditioning, performance can be compromised regardless of product choice.
Key: In the UK water hardness is usually expressed
as ppm (parts per million) CaCO3
Very. Around 70% of UK farms are using moderately to very hard water.
If you’re not testing, you’re guessing – and that’s a risk when margins are tight and timing matters.
Glyphosate has helped raise awareness but it’s not alone. Other systemic herbicides can also be affected, including:
In reality, these situations are limited – and variable water sources mean consistency is difficult.
They’re not a reliable solution.
They sequester calcium, iron, and magnesium ions before glyphosate and other susceptible actives are added to the tank, preventing herbicide lock-up. By acting sacrificially, they ensure herbicides remain freely available for uptake into target weeds, reducing the risk of insoluble salts forming on target leaves.
Once glyphosate is tied up, it can’t be recovered – so sequencing matters.
Poor water quality often leads to:
That means more cost, more time, and more pressure on spray windows later. More importantly it also increases the resistance risk.
| Myth | Fact |
|---|---|
| Citric acid fixes hard water | Lowers pH, but doesn’t stop glyphosate lock-up |
| Straight AMS solves the problem | Helps, doesn’t neutralise hard-water ions |
| Some glyphosates aren’t affected | All formulations are susceptible |
Clean Water. Clean Kill.
For more guidance, practical tips, and water testing support, visit the Clean Water. Clean Kill. hub below