Tests & Testimonials

Rock Dust Tests and Testimonials

Trial done by : Mr John Hamaker

Date : 1976 – 1977

Product : 10 Acres of Corn / Maize

Results : In an area of sparse rainfall, dry summers and with no irrigation, the corn produced 65 bushels per acre compared to yields of less than 25 bushels per acre from untreated soils.  Independent analysis revealed the following increases in nutrient levels compared to the same type of corn grown with the aid of chemical fertilisers – 28% more protein, 47% more calcium, 57% more phosphorus, 60% more magnesium and 90% more potassium.


Trial done by : North Carolina State University

Date : 1989 – 1990 and 1991

Product : Fraser Fir and Red Spruce trees

Results : Greenhouse experiments (1989 – 1990)  Five hundred five-year-old fraser fir and red spruce trees were batch treated with varying amounts of rock dust.  Six months later the survival rate of treated trees was 100% against the untreated control’s 87% for fraser fir and 77% for red spruce.  Growth rate increases showed an improvement of between 5% to 37% for the red spruce and 14% to 39% for the fraser fir against that of the untreated control batch

Field trials (1991) on 6,000 newly planted seedlings of fraser fir and red spruce.  After a period of 12 weeks the height growth of red spruce showed an increase of 27% and the fraser fir an increase of 19% against the untreated controls.

General appearance of treated trees was that of a very dark green colour and good flushing of tissues whereas the untreated controls appeared to be somewhat yellow and chlorotic


Trial done by : The Harding Brothers, Queensland, Australia

Date : since mid-1985’s

Product : Bananas

Results : Fertiliser application reduced by 80% resulting in appropriate savings in fertiliser costs and minimising environmental damage caused by run-off contamination.  Sixteen months after dolomite application was reduced by 50%, there was no sign of magnesium deficiency that had been a problem with chemical fertilisers.  The banana plants are healthier with 25% higher yields and 20% increase in growth rate resulting in an incredible 80% increase in production coupled with substantial reductions in fertiliser costs


Trial done by : Manchester Metro University – P Madeley

Date : 1998

Product : Cress

Results : The following section details the results for experiments comparing dusted & control samples in perlite growing medium.  Done in greenhouse in pots.  After +/- 6 weeks, a 55% difference in mean root length between the rock dust and control samples were seen.  The roots on the rock dust cress also have an increased amount of root hair suggesting that they were taking up dust particles.  (The uptake has been observed in the form of protoplasm).  This implies that the addition of rock dust was having an effect on the root development confirming the idea that addition of rock dust increases microbiological activity and thus stimulates root development.

The shoot length was very much the same being 59% greater, which is quite a large difference.

The weight at this time was significantly different by 50%, this implies an increased biomass in the plant and links closely with the fact that root and shoot lengths were greater


Other Results

Results of long term experiments released in 1986 showed that in a forest where pine seedlings had been remineralised the wood volume was 4 times higher than in untreated areas

Don Weaver grew 18-foot pole beans on remineralised soil and harvested two to four times the normal organically grown yield

Alan LePage of Vermont, USA, grew a crop of carrots measuring one and one half feet long with virtually no insect damage

Trials conducted by Mr O D’Hotman de Villiers in Natal produced beetroots weighing in at over 2 kg (very sweet and non-fibrous) and cauliflowers at 6 kg with exceptional taste

Trials conducted by Curtin University, Western Australia, showed five times the growth for the same species of trees with ‘potting out time’ being shortened from five months to six weeks