Blu-Mark is a ready to use blue dye to be used when spraying weed killer as an indicator to where weed killer has been sprayed. Once sprayed, Blue-Mark will last for one to two days before breaking down naturally in rainfall or sunlight.
This product is only licensed for sale in the Republic of Ireland
Why use Blu-Mark when spraying?
Advantages of using Blu-Mark dye.
- Avoid overlapping and re-spraying an area twice
- Easily see missed areas
- Naturally breaks down in sunlight or rainfall
- Greatly reduces spray drift














