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McHort ARE HERE TO HELP WITH YOUR POTTING MIX ISSUES! - Qualified advice from the most experience in the business

Qualified advice from the most experience in the business


McHort are industry experts on the physical, chemical and biological makeup of potting mixes.

We offer a suite of tests and an interpretation of the results that will enable you to fine tune your potting mix for both economy and performance.

We have over three decades of experience, both at home and abroad. We truly know what makes a good potting mix and how to achieve it cost effectively. For a FREE initial consultation, call Donald on 021 782250.


What you need to know about why our fertilisers are made the way they are!

It will help you choose exactly what is right for your crop, climate and cultural practice.

Don't compromise your crop by using a product designed for someone else growing a different crop using different methods in a different climate.

Pittosporum 'Sudden Leaf drop' syndrome

A word of caution. Every year at this time we get reports of Pittosporum, and other species, growing in containers suddenly dropping all their leaves! What we believe is the cause of this has been borne out many times after close investigation of the cultural practice. The scenario goes like this: Grower decides to prune rapidly growing plants to improve form and shape. In a effort to maximise recovery growth and volume grower applies a generous top feed of a fast acting fertiliser. Typically this would be a brand with a high soluble faction but sold often as a slow release product. The 'shock' of too much soluble salts, perhaps too little diluting irrigation or rainfall and insufficient time for the plant to adjust to a reduced leaf and stem volume but an undiminished root system, results in salts injury to the roots. The consequences of which are a 'Sudden Leaf Drop'

Avoid this catastrophic effect by delaying any top feeding to well after any severe pruning operations of at least 14 days and better still a month. When choosing a top feed avoid formulations with a high soluble faction, Apex Super Iron has less than 10% soluble component. Other popular brands can have as much as 50% soluble faction. Use only a modest application and irrigate the crop well post application. Check your top feed salinity by putting a teaspoonful in 200ml of water and test using a conductivity meter. Products with a high soluble faction will generate an almost immediate peak in Ec. ( conductivity). Those with a high percentage of coated ,encapsulated or bacterial released component will show a very small increase in Ec.

Buxus blight alert

Although the spectre of 'Buxus blight' is bandied about I personally have yet to sight, in New Zealand, a confirmed case. Now that might surprise you but it just goes to reinforce the value of a professional diagnosis. Clearly many, suspected, outbreaks are being misdiagnosed. If however you wish to avoid any disease of a fungal origin in your buxus whether in the garden or nursery there are a few do and don'ts that you can follow.

1. Never cut Buxus if the foliage is wet.Never work amongst wet foliage.

2. Delay any punning until the new growth has hardened up.

3.Do not prune and feed at the same time. Delay feeding for 14 days, at least, post pruning.

4. Practice scrupulous hygiene clean blades regularly and tidy up prunings.

5. Maintain vigor with side/top dress fertiliser of an appropriate type and rate.

6. Apply McHort Plant Soap to control biting and sucking pests such as scale.

Please note that despite claims to the contrary there is no eradicate fungicide treatment for Buxus blight.

The suprising Fungicidal effect of Plant Soap

Sometimes grower practice aimed at resolving a particular problem throws up and unexpected bonus.This is the case with local experience using McHort Plant Soap.

 For many years we have advocated the use of McHort Plant Soap as an alternative, non toxic, treatment for controlling biting and sucking insects on plant leaf and stem. It simply suffocates these insects as eggs, juveniles or adults. Having recommended this treatment to deal to an infestation of Spider mite on a pine seedling crop an unexpected bonus effect occurred later in culture. The Spider mite problem was addressed and later that same season, in autumn, the grower reported that treated seedlings had resisted the fungal disease botrytis 'Grey mould' . This was only observed because the Plant Soap application was a spot treatment and this bonus effect only occurred in those spot treatment areas. This is what we believe has occurred:

The McHort Plant Soap has a strong and persistent surfactant effect. That is water, whether rain or irrigation, rolls off treated foliage rather than hanging up as beads of moisture in the foliage. This de-watering effect denies fungal spores the opportunity to germinate on the foliage and infect the plant.

Drier foliage equals less fungal pathogen activity. In this case, there is no fungicidal effect, we simply deny the fungal pathogen the opportunity to germinate and infect. 

So why wouldn't you  use McHort Plant Soap not only to suffocate insect infestations but simultaneously prevent fungal attack! Better still investigate our Plant Soap and biological fungicidal combo of Plant Soap and TrichoSpray Nursery. When we combine the two the Plant Soap actually provides the Trichoderma a viable food source, in situ, to help rapid and successful colonisation of the leaf and stem surface effectively excluding fungal pathogens.This effect is described as niche exclusion.

Potting Mix and Crop Nutrition

Pest and Disease Suppression

Landscape planting and maintenance

Cut Flower nutrition, pest and disease suppression

Potting Mix and Crop Nutrition

Pest and Disease Suppression


Cut Flower Production


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