Zeolite is a naturally occurring material found in many countries around the world, as well as Australia in Northern New South Wales. It is very low in nutrients but contains some Potassium, a small amount of Calcium and is known to have a very high Cation Exchange Capacity (see Did You Know section below).
Zeolite – The Basics
Zeolite is a naturally occurring material found in many countries around the world, as well as Australia in Northern New South Wales. It is very low in nutrients but contains some Potassium, a small amount of Calcium and is known to have a very high Cation Exchange Capacity (see Did You Know section below). A high grade more pure form can be made in a laboratory for such uses as cleaning air supplies for pilots. This is termed a medical –grade oxygen.
Is Zeolite readily available?
Zeolite is mined, ground up, then bagged for sale as a natural garden additive. Because it is a natural product not all deposits have the same range of purity, so the quality is reflected in the price.
What is it used for?
Zeolite has many uses apart from Horticulture and general gardening. It is also used in many every day products some of which include:
- Kitty litter where it is super absorbent as well as holding odours so it acts as a deodorant in the non-clumping form
- Pool filters instead of sand to collect pollutants
- Water purifiers removes toxic wastes from water & fly ash
- Nuclear Absorbent used with the Fukushima Disaster
- Odour neutraliser removes odours and freshens air (e.g. under chicken pens)
- Vermaculture (Worm farming) absorbs heavy metals, and stabilises the pH level
- Washing Powder and Detergents. This is the largest single use for Zeolite
- Cement as an additive – to make it easier to work with
Zeolite is used to absorb and hold nutrients and water but also allows plant roots to absorb the dissolved nutrients from the Zeolite for their growth.
Some of the uses in Horticulture are:
- Turf – Zeolite is mixed with the soil before any turf is laid at the rate of 250 -750 grams per meter of soil. For existing lawn, the Zeolite is applied after the lawn has been aerated, and is often mixed with fertiliser and/or sand at 250 to 1kg per square metre of soil.
- Garden beds – Zeolite is generally mixed into the top 10-15 cms of soil together with any organic manure or other fertiliser to improve water holding capacity and nutrient retention.
- Planting – Zeolite can be put into the bottom of the hole, mixed with the soil then the new plant installed
- Compost heaps – Zeolite can be used to control the leaching out of Nitrogen by absorbing Ammonia which it then converts to Nitrogen delivering nutrition to plants on demand. It is in this process that Zeolite acts as an odour reduction agent or absorber
- Mulch – Zeolite is normally used to retain moisture and nutrients. It can minimise splashing of fungal spores onto plant foliage from the bare soil. This helps with reducing plant root rot from Fungi like Phytophora spp
- Potting mix – Zeolite reduces the added amount of fertiliser required (especially Nitrogen) because it retains nutrients that would otherwise be lost through the leaching process.
*When Zeolite is used in Horticulture it is primarily from a natural source so it is generally accepted as an organic material for the certification process.
Health and Safety
Zeolite is not toxic in itself; it is the milling process turning it into a fine texture that the user needs to be aware of. It is recommended that a mask be used to stop it entering the mouth and lungs which may cause irritation.
Some people have been know to ingest Zeolite to soak up Alcohol after a big night of drinking. Supposedly you don’t get a hangover.
Today’s Did You Know…?
There are seven cations in the Cation Exchange Capacity. These are positively charged particles that measure and influence the soils ability to hold on to essential nutrients.
- Hydrogen (H)
- Aluminium (Al)
- Calcium (Ca)
- Magnesium (Mg)
- Potassium (K)
- Ammonia (NH4)
- Sodium (Na)
So here’s how it works
The Cations (positively charged nutrients) are attracted to Colloids (negatively charged particles) of soils and other material. These colloids are basically a food storage facility for nutrients that plants can access when they are released (or exchanged) into the soil water. These cations (nutrients) in solution are now available for the plant to use. The ability of each particle (colloid) to hold cations (nutrients) is limited by the number of negative charges they hold on their surface.
“If there is a concentration of one particular Cation in the soil water, those cations will force other cations off the colloid and take their place.
The stronger the colloid’s negative charge, the greater its capacity to hold and exchange cations, hence the term Cation exchange capacity (CEC).”
Soil is created from the erosion, weathering and disintegration of rocks such as Granite, Shale, Quartz and Limestone over millions of years. The base rock is weathered by rain, sunlight, ice, organic acids (from plants decomposing that produce a weak acid called Humic acid), temperature (when the rock has the forces on it of expansion and contraction as the temperature changes), and other factors.
Basic Soil Properties
What gives a soil its basic properties?
Soils are created from the erosion, weathering and disintegration of rocks such as Granite, Shale, Quartz and Limestone over millions of years. The base rock is weathered by rain, sunlight, ice, organic acids (from plants decomposing that produce a weak acid called Humic acid), temperature (when the rock has the forces on it of expansion and contraction as the temperature changes), and other factors.
The soil type in a garden is determined by the rock that it was weathered from and how and where it was deposited. If the parent rock was a limestone then the soil will most likely be a sandy soil.
Three basic soil types exist in most gardens but can be further classified into Silty Soil, Peaty Soil and Chalky Soil though the three are less common in the back yard.
Of course, the soil in your garden may have been altered by people adding top soil, compost, mulch, green waste etc. to alter and improve the basic properties of the soil
The proportions of sand, silt & clay in your garden can be determined by placing some soil in a tall thin clear container, eg. an old milk bottle, shaking it well (not stirred) with some water, and letting it settle overnight into its respective layers. Measure each layer and determine the % of each of the sand, silt & clay and then use the below diagram to determine what category you soil falls into.
In NSW and north, the soil is slightly acidic so the plants that grow naturally in it prefer a slightly acidic soil. At 6-6.5 the soil is slightly acidic and all the nutrients are available in enough quantity without being in excess or deficient.
In areas where the soil is derived from limestone, (eg. in SA), the plants prefer the slightly alkaline soil such as Azaleas & Rhododendrons.
Water can also change the pH of the soil as well as added unwanted minerals.
Town water is quite variable depending where it is supplied from.In Brisbane, the water comes from a wide range of reservoirs.If you are watering your plants from a bore then it commonly has excessive iron in it. This Iron is not normally available to plants as it is locked up chemically but will discolour the leaves of plants.
To be sure of the water you will be using you will need to get it tested mainly for pH levels.
A local Nursery will often test the water for free or a nominal charge and then you will have a base level to work from.
The cheap pH kits based on a piece of soil that you add some powder to and then check the colour against a colour chart, are crude and will only give a value of + or – 1 unit, and about 30% of Australian males are partly colour blind so may not see any clear colour.
Today’s Did You Know…?
An amazing example of weathering and erosion and deposition of sediment is the Bodélé Depression. Located in Chad, in North Central Africa on the southern edge of the Sahara Desert, it was once a part of the Mega-Lake Chad. Drought and irrigation eventually reduced this great lake to 5% of its former size leaving silt and sediment to scorch and dry in the African sun and later to be eroded away by the wind and is deposited thousands of miles away in the Amazon Rainforest and the east coast of the United States.
Believe it or not, this sediment is “Diatomaceous Earth” and provides a valuable source of nutrients for the forest and the soil. (See the previous newsletter on Diatomaceous Earth)
“In winter, the depression produces an average of 700,000 tonnes of dust each day (Todd et al., 2007).”