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Optimising spray coverage

Optimising spray coverage

Grant Beare - 25 years of invaluable knowledge


Grant Beare, spray guru and certified industry trainer, is based in South Auckland.  Grant has been repairing spray equipment for growers all over the country since 1994.  With 25 years’ experience under his belt Grant has seen the results of effective and not so effective spray coverage on plants. He has experience with both indoor and outdoor growers.

Spraying the right volume of water per m2, using the correct nozzles, spray boom and pressures for effective coverage are areas Grant believes some growers could gain improved outcomes from. 

Grant advisers’ greenhouse growers spraying full canopy crops to use .4 fan nozzles with 110-degree spray angle, approximately 300 mm apart, ideally connected to Braglia Nozzle holders, on the spray boom.  Every second nozzle on the boom is a twin jet fan nozzle with the same 110-degree angle but with .2-hole outlet either side.  By using water sensitive paper through the canopy of the plant Grant has been able to prove to growers how effective the coverage is carrying out his advice.  Other important factors include the distance to the target and bar pressure.  Understanding that all products are not entirely the same is another aspect for consideration.

Grant uses the TRW (Tree row volume) technique to calculate the volume of water that should be applied to every m2 of canopy.  Row length x height (of what you are spraying) x double row (you are spraying two sides at once) x the number of rows.  Approximately 2000 litres of water should be used per ha of an adult tomato crop, for effective full crop coverage.  You will have to calculate the speed you need to walk to apply the required volume of water/product, unless you have a robot sprayer. Apart from advising growers on optimum spraying techniques, Grant will also calibrate spraying units.

Application of every spray is important if you want to have successful control of pests and diseases.  Grant will help you understand the best and most effective way to spray your crop. 

With whitefly appearing to be a major threat this summer, accurate application is of the utmost importance.  Well worth calling Grant!

For more detailed information on this article or for spray application advice please contact:

Grant Beare

m: 021 020 08040

e: grant@educhem.co.nz


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Article Written and compiled by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower