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).”