Rock Hard! The story about some of our South Island Stone

South Island Stones - A Rock Hard Story about how our South Island Natural Resource is collected and how we are ensuring the sustainablility for generations to come.

The Origin


Pebble, stone and rock has been in the making for millions of years, originating in the Southern Alp and thus beginning its journey.

These mountains are still being pushed up and ground down by 2 cm per year. Avalanches and floods dislodge and scatter this Rock and Stone Kilometers down through magnificent waterways of Glaciers, rainforests and raging streams before being deposited on the wind sweep beaches of the West Coast of the South Island.

Our supplier works hard to harvest these natural products, so we can bring them to you and with the piece of mind that ensuring the sustainability of this amazing commodity is paramount.

South Island stone offers a range of colours that we don’t often see in our North Island counterparts. This means that you can have the durability of stone with the element of something a little bit unique in our North Island region.

Some of the range we do.

Waitaha Split/Waterworn Paving

The Waitaha stone is sourced from a massive slip that happened in the 1938 earthquake in the Whataroa region. This slip literally made half a mountain fall over into the valley below and now a rugged mountainous steam flows out from it. Almost all the rock is high grade Biotite Holecast Schist -some smothered in Garnets, some that we call green schist and a number of others colours. This gets rumbled down the river to our supplier who then get out the hammer and chisels and start splitting. They work across the river bed hand selecting the best rocks and use the chisel to slice off slabs of paving stone. They then load into a wheel loader bucket which crosses the river bed to the Weststone base on the side of the river. It gets loaded onto a truck and brought back to the Depot in Greymouth where it is all sorted and stacked on pallets ready to be barged to Auckland Landscape Supplies in the North Island.

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Beach Stones

These have a much longer journey than the Paving stones before we can extract them. These travel many kilometers down the rivers and are washed out into the Tasman Sea. The Stone is then carried northward and gets washed up onto the beach’s where pickers on 4 wheeler motorbikes can sort though the stone and load into the one tonne sacks that are delivered to Auckland Landscape Supplies yards. With up to 3 million tonnes of silt and aggregate getting washed out of each West Coast River each year into the Mighty Tasman Sea we have no chance of running out.

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Have a look at the photo on the left and right.  When we tell people that the flat beach stone is hand picked off the beach, they naturally picture in their minds a stony beach which has no sand. (Typical English beach). This is not the case.  The flat beach stone is scattered all the way along the beach at a frequency which can be seen in these photos.  The pickers walk and drive for miles to harvest enough stone to send to Auckland Landscape Supplies.  The resource consent stipulates that no vehicles are allowed on the beach other than a four wheeled quad bike.  The quad bikes can hold four buckets at a time and therefore many trips back and forth to the trailer in the car park are required to fulfill an order for Auckland Landscape Supplies.  That being said, remember although the supplier has to walk for miles to harvest this particular stone, more gets washed up with every full tide.  Stone is constantly being washed into the Tasman via the West Coast rivers.

Omotu Stone


Omotu Stone comes in two sizes 18mm to 40mm and 40mm to 80mm.  As mentioned above,  New Zealand's Southern Alpes rise by 2cm per year. Now the laws of natural attrition dictate that due to avalanches, floods glacial activity etc, many different types of stone are scattered into many different alpine streams and rivers. As theses rivers make their way down the mountains they join together with other small rivers at multiple points along their journey. Resulting in several large rivers exiting New Zealand's mountanous regions into the sea.

One such river is the mighty Grey River coming out of Greymouth (mouth of the Grey River) Dredged out of the Grey River is thousands and thousands of tonnes of a stone we call Omotu Stone.  This stone is made up of many different types of stones originating from different parts of the Alps.  They have all rumbled down their feeder rivers and then rumbled down the Grey River to a catchment point where they are pulled from the river, screened into different sizes and then barged up to Auckland on a 6000 tonne barge.  The Omotu Stone is then delivered to Auckland Landscape Supplies' yards on large truck and trailer units, this is where it lies in wait to bring a bit of South Island beauty to your little piece of paradise.

Frequently Asked Questions About Soil

  1. What are the main differences between Garden Mix, Garden Magic and Premium Lawn Mix?

    The main differences between the three products are the blend of the key inputs, Compost, Pumice, bark and slow release fertilisers. All three products are designed for their end use.

    • Garden mix is the premium garden product, made to ensure the mix once applied to the garden retains moisture but allows adequate drainage to prevent ponding. The blend of products also ensures that garden mix has good physical structure that maximises root growth while giving excellent root support and nutrient release giving plants a solid foundation to grow from.
    • Garden Magic is similar but its inputs (slow release fertilisers) are cheaper, making the product more affordable – however it will need more regular applications of extra fertiliser.
    • Premium Lawn mix – like Garden mix is specially designed for lawns. The blend of inputs are designed to make the mix easy to rake out and spread for the applicator, however ensuring there is enough compost and goodness in the lawn mix for rapid establishment of grass seed (or ready-lawn) and an enduring healthy lawn.
  2. Do you add anything to the Compost?

    • We do not add anything to our finished compost. Our compost is made predominantly from green waste and a smaller amount of food waste and wood waste. These materials are blended together and composted under forced aeration. Our composting process takes four months. Once the process is complete we screen the product, removing any oversize material (wood waste) and contaminates that may be present. Our finished product is then sold in bulk or blended to form Garden and premium lawn mix’s.
  3. Does it smell bad?

    • Finished compost should smell earthy. Garden and lawn mixes can have a slight odour which is caused by the micro- organisms in the mix’s – breaking down and utilising the slow release fertilisers that have been added. This is a natural process of nature and ensures there is a steady release of nutrients for the plants once they are planted.
  4. How are these mixes 100% Weed Free?

    • Our compost process is carefully monitored. We measure the temperature of our piles and the oxygen content within the pile to ensure our piles reach 60 degrees for longer than three days and that the piles have sufficient oxygen to ensure the piles are composting aerobically. We also cover our piles with a bio filter. The bio-filter has two purposes: 1) to ensure odours are totally broken down before they leave the pile, and 2) to act as an insulator to ensure the outer area of the pile reaches the required temperatures to ensure weed seeds are heated to the correct temperature to ensure they can’t survive. As a safe guard, after our primary composting time period, our piles are turned moving the outside to the inside and vice versa, before being reheated. This ensures all parts of the pile have had a period of composting within the middle structure of the pile.
  5. What Quality standards does GMA meet?

    • Envirofert composts to the New Zealand composting standard (NZS 4454). We test our product up to three times during production. At the start to ensure we have our blend of inputs correct, when we move the compost material from active composting to maturation, and we test our finished product. All testing is done by Hill Laboratories in Hamilton.
  6. What is the PH Level once it is ready for the garden?

    • The pH of finished compost is normally between 7 to 7.3. This is neutral or close to neutral. Most soils are acidic < 6, – so compost acts as a natural liming agent raising the pH of soils. Most plants prefer a soil pH of around 6.4. Adding compost helps create the right environment for maximising plant growth. Plants that may prefer more acidic conditions (such as those that naturally grow in heavy clay and leached soils) can also benefit from a light application of Ammonium Sulphate or elemental sulphur to depress the pH of the immediate soil environment. Compost will still benefit these plants.


88a Merton Road,
St Johns, Auckland
09 951 4089

Mt. Roskill YARD:

52A Frost Road,
Mt Roskill, Auckland
09 951 4089


163 Airfield Road,
Takanini, Auckland
09 951 4089

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