Special feature: know your nozzles

Hardi Australia offers expert advice around tips for achieving the best application and results when it comes to achieving accuracy in spraying


When it comes to achieving accuracy in spraying, particularly when using different agricultural chemicals and fertilisers, it can be difficult to know what nozzle is best for your application. Hardi Australia offers expert advice around tips for achieving the best application and results.

Spraying agricultural chemicals is a fine art that requires a thorough understanding of the chemistry being used, sprayer and capacity, including speed, coverage, and drift control in order to ensure accurate application of product, as well as reduce wastage. A lot of that art comes down to knowing what nozzle type and size is required to undertake the job at hand.

Hardi Australia, which manufactures the majority of Hardi’s sprayers and booms sold in Australia and New Zealand at its Adelaide facility, is an expert in application technology and achieving the control and accuracy required for optimal sprayer performance, with a wide range of application and nozzle technologies to meet your needs.

The Quintastream nozzle provides five streams of liquid to reduce leaf scorching and improve penetration through to the soil

The basics

The three main pesticide groups are herbicides, fungicides, and insecticides. The application of fertilisers through the boom is also becoming more common.

The pesticide dosage, otherwise known as application rate, is the amount of pesticide required for a given area of a particular crop. The application rate may have a minimum and maximum value and a recommended water volume. The application rate depends on crop and pest stage, weather conditions and application technique being used.

A sprayer and its operator’s capacity are largely dependent on tank and boom size. Larger booms allow greater coverage per pass and a larger tank allows greater coverage between fillings, which is often the most time-consuming component of spraying, especially when water access may be limited. Most importantly, though, the correct nozzle for the job must be chosen.

The Hardi Twinforce boom uses a curtain of air to push the droplets down into the canopy

Three critical criteria when spraying are:

  • Boom height: most nozzles are designed to be used 500mm off target, as this provides double overlap for the best coverage. Hardi’s Autoheight and AutoTerrain systems ensure that the boom stays at the recommended and desired height throughout the operation.
  • Application rate: while lower water rates may allow for more passes per tank, higher water volumes allow for a greater amount of coverage per area covered.
  • Spray quality (or droplet size): the droplet size required is generally outlined on the label of a chosen chemical, which is dependent on crop and target type, and weather conditions.

There are two further criteria – speed and pressure – however, these are a function of, and determined by, the desired application rate, and spray quality.

Hardi nozzles follow the ISO 25358 standard for crop protection equipment, which cover seven size classifications, ranging from very fine to ultra-coarse. The challenge is that no nozzle will give you all spraying options and that is why you sometimes have to compromise.

Different nozzles are suitable for different chemicals and applications

Technology is here to help. The Hardi Twinforce boom provides air assistance – with a tapered airbag along its length to ensure consistent air volume and velocity, it uses a curtain of air to push the droplets down into the canopy, increasing coverage and reducing drift.

Hardi H-Select includes four nozzle switching, allowing for a huge variation of speed and pressure, providing turn compensation, variable rate technology, and the ability to change droplet size on the fly from the cab.

Choosing nozzles

Always follow label recommendations regarding application rate and required spray quality. If there is any uncertainty, contact your agronomist or the chemical manufacturer for clarification.

Hardi has a nozzle for every application.

FlatFan nozzles provide spray quality from fine through to very coarse and is recommended for all types of pesticide application where optimum coverage is demanded. However, they have very little drift control in most applications. Available in sizes 0075–10.

LowDrift nozzles provide spray quality from medium to very coarse and are recommended when optimum spraying conditions cannot be achieved (risk of drift) and spraying cannot be postponed. Available in sizes 010–05.


MiniDrift nozzles provide spray quality from medium to very coarse. They are standard on all Hardi sprayers as they meet the widest range of requirements for all applications. Available in sizes 015–05.

MiniDrift Duo nozzles have two orifices, and spray 30 degrees forwards and backwards, allowing better penetration of dense canopies and better coverage on vertical targets. Available in sizes 02–05.

NanoDrift nozzles provide spray quality from medium to extra coarse. New to the market, the NanoDrift is a short-length, full-air induction nozzle, with very few driftable fines, providing up to 90% drift reduction. Available in sizes 02–05.

Fertiliser applications can be applied as a foliar using any of the Hardi nozzles, however, when soil application is required, Hardi offers the Quintastream nozzle: five uninterrupted streams of liquid distributed at various angles to reduce leaf scorching and get the product through to the soil.  

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