Nov 2020

The Benefits ReduSystems Greenhouse Coatings have in NZ

The Benefits ReduSystems Greenhouse Coatings have in NZ

Jason Culbert, Head Grower, Underglass Explains


New Zealand’s unique, unpredictable summer conditions always make it a challenge to grow aging glasshouse tomato crops.  For one of New Zealand’s largest high-tech commercial tomato and cucumber growers ReduFuse offers a solution to reduce stress and maintain fruit quality, even increase yield during this time.  Jason Culbert, Head Grower of Underglass Karaka, part of the NZ Hothouse group, kindly offered an insight into ReduFuse coatings and other ReduSystems products used to protect their summer crops.  


Jason has been with the company for over 17 years. He is responsible for 18 ha of growing area over two major growing sites, which grow multiple tomato and cucumber varieties.  He has vast experience and is one of New Zealand’s most well-respected high-tech greenhouse vegetable growers.  Underglass first started applying ReduFuse to some of the greenhouse tomato crops in 2013.  By 2015 it was rolled out as standard practice and has been applied ever since.  Below is some direct feedback from Jason regarding his observations over the past seven years.


What ReduSystems products do you use?

We currently use ReduFuse, with trials of ReduFuse IR. 


What time of the year will you apply ReduFuse and then remove the coatings?

They are applied from September to November and removed using ReduClean from April to May.


What was the reason for your initial use of ReduSystems coatings?

It defuses light into the crop and lowers leaf temperature.


What other types of shading did you use on the greenhouses before applying ReduSystems coatings? 

We sprayed whitewash in the early days when growing on pumice bags to get the crops through the heat of summer.


What Benefits were identified after you first started using the coatings?

Its improved pollination, reduced Blossom End Rot (BER) and the main benefit is larger fruit and an increase in Tag 1 grade fruit.


What is the largest difference using coatings compared to when you had no coatings?

Defusing light in, rather than reflecting light out (crops are able to make more sugars = larger fruit size, more production).


Does the plant look physically different?

Yes, the plants have more vigour & longer leaf length.


Is the plant health/vigor better and if so, how do you see this?

Yes, because we can open the crop up due to the higher leaf index, sun damage does not happen with the correct coating.


What effects on evaporation and possibly plant temperature have you identified?

Its proven, ReduFuse lowers plant temperature.


What are the effects on the greenhouse climate: temperature, humidity?

Slightly lower temps are what we have experienced with the ReduFuse coatings.  ReduFuse IR lowers temps for sure, but it does take some light away. With climate change I believe more growers will use ReduFuse IR in the future.


Does the coating have a positive impact on working conditions for employees in the greenhouse?

It (ReduFuse) takes the edge off the intensity compared to not using a coating.


Did the ReduSystems coatings meet your expectation’s?



What advice or recommendations would you have for other growers when considering using ReduSystems coatings?

They have a lot of products and advise. Every property is slightly different.  I advise trialling small areas, with different rates of the products you a trying. Our two sites use different rates of ReduFuse, to achieve the same result. Coatings change the climate in the greenhouse and are an investment, so choose wisely.






How is it applied to your greenhouses?

It is either sprayed on with roof washer machine or by helicopter.


What is your preferred option?

Roof washer.


What are the reasons for using both options?

Applying by helicopter takes less time to get the product on, also not all growers have access to roof washer machines. 


How many buckets per ha do you apply?

10 to 18 buckets per ha crop.  We apply a minimum of 12 buckets per ha with the roof washer.


Cover photo: Jason with a crop that was planted over 12 months ago.  For the last two months of the crop cycle ReduFuse helped to maintain fruit quality



Other products used in New Zealand are ReduSol.  This is very popular with flower growers and nurseries.  It is also very popular for shading side walls at vegetable growers’ properties.  The positive impact that all ReduSystems coatings has had in New Zealand for Greenhouse crops is evident by their popularity.    


For more information:

+3113 507 53 99


ReduSystems products are distributed by Horticentre Group in New Zealand


About ReduSystems®
ReduSystems® is a brand of Mardenkro B.V. ReduSystems enables growers to make optimal use of sunlight in the greenhouse throughout the year. The coatings influence the light and heat of the sun during every season to help optimise climate conditions for the crop inside the greenhouse. From a cooler climate in summer and more-light in winter, to diffusing the light and influencing the light spectrum


I appreciate your comments.  Please feel free to comment on the grower2grower Facebook page:


Article Written and compiled by Stefan Vogrincic, Consultant, Grower2Grower

Article Edited by Marie Vogrincic, Editor, Grower2Grower


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