Frequently Asked Questions


Foliar Applications

How does foliar feeding work?

Foliar fertilisation is the application of micro (boron, chlorine, copper, iron, manganese, molybdenum and zinc) or macro (nitrogen, phosphorus and potassium) nutrients to plant leaves. 

The use of foliar  applications of macro- and micro-nutrients is not a new concept; it has been around for decades – but as with all new product generations, the foliar spray technologies that are on the market today bear little to no resemblance to the crude products of the past. 

Foliar applications ensure direct and indirect cellular uptake:
● through the stomata, trichomes, leaf wax layer penetration (cuticula)
● or through movement in the xylem (passive) or phloem (active)

The method that the plant will use is dependent on the formulation of the application, which is an example of how the original products have developed through research to achieve increased absorption rates and means of translocation to growing points and production, improving nutrient use efficiency (NUE). 


Why would you choose foliar feeding?

Foliar feeding can be beneficial and ensure a more consistent uptake of nutrients than through the root system when: –

  • Low evaporation
  • Too wet/dry substrate
  • Weak roots (susceptible for diseases e.g.)
  • Quick plant growth
  • Young and underdeveloped roots
  • High pH in the root environment
  • High pressure on the crop due to stress factors
What are the benefits of foliar feeding?

There are many benefits to foliar feeding: 

  • Quick intake of nutrients
  • Input waste reduced as none is lost and locked up in the soil and no environmental run off.
  • Low amount of plant energy needed for transport of nutrients, because the nutrients are in the right place immediately
  • Also, non-mobile nutritional elements remain in the plant
  • High utilization of nutritional elements
  • No risk for fixation in the soil or substrate
How much of the foliar feed is utilised by the plant?

Trials of foliar nitrogen have demonstrated that 90 – 95% of fertiliser is utilised by the plant, which compares to only 10 – 55% of soil applications.

What are the perceived, historical disadvantages?

The concept of foliar applied preparations was based on science, the initial foliar application products had their drawbacks, such as leaf scorch, low active volumes per application and not being rain-fast, which tarnished the overall concept and commercial uptake.

Over the last thirty years, reams of research has been carried out to address many of these issues, resulting in today’s products that have been developed using modern chemical and biochemical engineering which:

  • Has virtually eliminating leaf scorch
  • Is rain-fast in 30 minutes
  • Allows full treatments of nutrients, including nitrogen, in a single dose without scorching.

Additional micronutrients and biostimulants can be added to these mixes resulting in third-generation products that can deliver a full crop nutrition programme directly onto the crop’s canopy, promoting crop growth and development, seconds after application.

Due to our unique, advanced formulations technology our products are readily absorbed and translocated throughout the plant without risk of crop damage or scorch. Effects are effective, persistent and long-lasting.

Do wetting agents improve the efficacy of foliar feeding?

Our products are formulated to optimise leaf uptake, absorption and translocation in the plant and do not require the addition of wetters or spreaders.


Can foliar application be delivered through a conventional sprayer?

Foliar applications can be delivered using a regular sprayer and can be carried out from the 1st leaf growth stage through to harvest.

In many cases, multiple foliar feeds can be tank mixed to avoid multiple tractor passes, BUT it always necessary to check the application instructions and carry out a ‘jar’ test. If there is any concerns or doubt, consult the manufacturer before tank mixing.


Foliar Nitrogen Applications

What is foliar N?

Foliar N is the abbreviated term given to foliar applied nitrogen that is sprayed directly on to the crop’s canopy, delivering nitrogen to promote crop growth and development. 

Additional micronutrients and bio-stimulants can be added to these mixes to support the crop’s growth, root development and to reduce the effects of environmental stresses.  

When is the best time to apply foliar applications including Foliar N to crops?

The best time of day for foliar applications are early mornings or late afternoons, when humidity is high and the leaves are in a state of full turgor, with their cells full of water.

Is foliar fertilising just for ‘top up’s’ or can a more profound responses be achieved?

Using OptiYield foliar feeds can eliminate the need for further soil applied nutrients even for macronutrients like Nitrogen. OptiYield Folia-N can provide 50kgs on N in a single dose through the crop canopy without risk of scorch or crop damage and provide 95% Nitrogen Use Efficiency (NUE).

What effect can foliar fertilisation have on yields?

Research and farm trials have shown that foliar feeding can increase yields from 12% to 25% when compared to conventional fertilisers.

Folair application