Horticultural Applications

Greenhouse Uses - Ornamentals

Apply as per spray method, coating foliage to assist with mealy bug and other sucking insects.   For faster kill rates, we have had outstanding success blending the recommended rates of DE described below with 5mls per litre of Pyrethrum completely eliminating mealy bug and midge fly from our hothouses.  The addition of Pyrethrum aggravates and stimulates insect activity enabling the DE to do its work faster.

Timing of Applications – Ideally, insecticides should be applied when there is no wind and when bees are not visiting the area.  The time and intensity of bee visitation to a given crop depend on the abundance and attractiveness of the bloom.  .  In general, evening or early night applications are the least harmful to bees.

Understanding the biology and life-cycle of the insect pest to determine the best time for application and using the least toxic approach to preserve ‘good’ insects such as ladybugs, spiders, bees, praying mantis etc that are beneficial to your plants.  

DE is absolutely fine to use in conjunction of liquid fertilizers and wetting agents such as Deepak etc.  Like all spray applications do not use in full direct sunlight or temperatures over 33C.  We recommend before treating a large area treat a few plants to ensure plant safety.   

Ensure all spray equipment is cleaned after use to avoid DE leaving residue deposits in the tank, pump, nozzles etc.  Simply flushing with clean fresh water for a minute or so will suffice.

General Horticulture

Diatomaceous Earth has a multitude of helpful and practical uses in horticultural applications - these are well documented on overseas websites.  www.denz.co.nz Limited cannot vouch for the authenticity or factual basis for these uses and suggest that customers assess their suitability for themselves. 

Unfortunately, in New Zealand due to the ACVM Act (Agricultural Compounds and Veterinary Medicines legislation) we are unable to claim the majority of these uses - technically.  The ACVM has re-classified our natural and organic Diatomaceous Earth as an Agricultural Compound - something of and irony in itself!  Consequentially we have no alternative but to work through the complex and expensive process to register it as such.  Pending registration we have been legally bound to remove meaningful applications and information from our website until registration is granted.  As a result we apologize for the lack of constructive detail in this section of our website.  We would be grateful for your patience as we hope to have a resolution to this situation in the coming months. 

Note: DE will not affect the egg stage of most insects and may need to be re-applied to impact the next generation or hatch.

Application rates of sprayer – weigh 60gms / 180mls in a 15l backpack sprayer.  800 – 900gms of DE mixed in a 200 litre automated sprayer.


Application rates for brushing application - 1 cup applied to ½ gallon of water creates an effective solution.  Maintain regular stirring or agitation during use to prevent DE settling.


With careful observation of your plants you will discover the perfect times and volumes to apply Diatomaceous Earth to gain the most benefits.  

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