When relying on herbicides to manage weeds in pastures, it’s crucial to get the best bang for your buck. Maximising the effectiveness of your spray applications not only helps reduce weed pressure but also keeps input costs in check and improves paddock productivity.

One of the simplest ways to do this is by using the right spray additives alongside your herbicide program.

Spray additives – including wetters, oils, and penetrants – have become essential tools for improving herbicide uptake and ensuring consistent results, especially in tough conditions or when targeting hard-to-control species. From broadacre settings to pasture systems and horticulture, they help herbicides stick, spread, and enter target plants more efficiently.

Our top 6 spray additives

What are adjuvants – and how do they work?

The term adjuvant covers a broad group of products added to herbicide mixes to improve spray performance. They come in several forms – the most common being:

Wetters (Surfactants): These reduce surface tension, allowing spray droplets to spread out and coat leaves more effectively. This increases contact with the plant and supports better absorption, especially where leaves are hairy or waxy. Non-ionic wetters are commonly used across pasture and cropping systems for this reason.

Spray Oils (Additives): Typically made from mineral or vegetable oils, these work by softening the plant’s waxy surface, helping the herbicide penetrate more deeply into plant tissues. They’re useful for improving uptake in conditions that make translocation difficult, like dry weather or slow-growing weeds.

Penetrants (Organosilicones): These are high-performance adjuvants designed to rapidly spread the herbicide across the plant surface and push it deeper into the foliage. Penetrants are ideal when tackling tough-to-kill or herbicide-resistant weeds and are especially helpful in challenging spraying conditions.

Tackling Common Spray Challenges

Even the best herbicide can fall short without proper delivery and uptake. That’s where adjuvants step in. Here are some common problems they help address:

Hydrophobic leaf surfaces: Some weeds naturally repel water, making it difficult for herbicides to stick and absorb. Wetters and oils help break through this barrier by improving droplet spread and reducing bounce or runoff.

Rainfastness: In variable climates, rain after spraying can wash herbicides off before they’ve had a chance to work. Using an adjuvant with rainfast properties helps protect your investment and reduces the risk of environmental runoff.

Spray drift and evaporation: In windy or hot conditions, herbicide droplets can drift away or evaporate before they hit the target. Adjuvants help with droplet retention and slow down evaporation, keeping more product on the plant where it’s needed.

Improved uptake: Ultimately, adjuvants support faster and more complete herbicide absorption, leading to a more reliable and longer-lasting weed knockdown.

Choosing the Right Product

Selecting the right adjuvant comes down to understanding the conditions you’re working with and the nature of the weeds you’re targeting.

Wetters like Wetter 1000 or Wetter 600 are a smart choice where dense foliage may prevent good coverage. They help the herbicide spread and stick evenly, ensuring every leaf gets treated.

Spray oils such as Trooper Spray Adjuvant or Enzo Spraying Oil are ideal when you’re focused on improving penetration, especially in dry conditions or where waxy leaves are present.

Penetrants like Techdeck Penetrant are the go-to when dealing with resistant or tough weeds, offering excellent spreading and rapid uptake even in hot or wet weather.

Final Thoughts

Incorporating the right adjuvant into your spraying routine can make a world of difference. Not only do these products improve weed control outcomes, but they also support more efficient herbicide use, which is better for your wallet and the environment. Whether you’re managing pastures, broadacre crops, or a mix of both – the smart use of wetters, oils, and penetrants helps unlock better value from your herbicide program.

Need help choosing the right adjuvant for your next spray? The Notman Pasture Seeds team is here to help – reach out for expert advice tailored to your farm.