I was introduced to Zeolite and Enfield Produce in Sydney by a bonsai mentor Rob Clausen and have been using 2-4mm Zeolite at about a 10% additive for about 30 years. As a relatively inexpensive mineral additive it attracts and retains fertilisers and releases them when the plant needs it, preventing soil nutrient leaching. Zeolite is suitable for virtually all plants and is especially popular for growing bonsai and roses.
Zeolite is a multifaceted volcanic material that offers nutrient retention, aeration and water retention, and due to its highly porous nature (and the capillary effect), it serves as a wetting agent.
It is a highly porous, negatively charged (anionic) mineral capable of capturing positively charged molecules (cations) such as nitrogen and potassium. It then, gradually releases them back into the soil, resulting in enhanced yields and a more effective use of nutrients in your soil.
Zeolite remains intact over time (so you don’t lose it if you recycle your bonsai soil), continually contributing to soil structure. Depending on its moisture content, it can retain water when saturated or promote aeration when dry. This makes it a flexible soil addition, allowing you to adjust its concentration to match your watering style. For instance, those who water lightly might use more.
Zeolite is neutral and won’t adversely affect your soil microbes or plants. It can be incorporated into a soil mix or applied as a mulch layer. I have observed that using Zeolite in your mix or on top of soil appears to reduce the occurrence of curl grubs and repels birds and small animals.
An open mix with high air porosity and good drainage is important to stimulate root growth and prevent many root diseases but it also leads to rapid leaching of nutrients away from the root zones of plants. Zeolite prevents this by attracting and holding the nutrients preventing them from washing through the container.
Zeolite works as a fertiliser battery, charging when free nutrients are available, holding them from leaching and releasing them to plant demand as required. Zeolite is not affected by temperature and buffers the dumping of nutrients by coated fertilisers under hot conditions holding them for use by the plant instead of just running away.
In summary the main features and benefits of zeolite are:
• Captures nutrients lost when coated fertilisers dump in tropical conditions
• Attracts and retains nutrients for use by plants.
• Reduces nutrient loss through leaching.
• Slowly releases nutrients as plants want them.
• Improves cation exchange capacity (CEC)
• Buffers ammonium in mixes.
• Improves the quality of runoff water.
• Improves the value of fertiliser.
• Assists water infiltration.
• Strong capillary distributor.
• Improves plant performance.
• Does not break down in the mix.
Zeolite retains moisture really nicely, meaning it can also act as a moisture control in mixes, making it useful for both dry and moisture loving plants. Zeolite reduces the added amount of fertiliser required (especially nitrogen) because it retains nutrients that would otherwise be lost through the leaching process.
Disclaimer:
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.
References:
Organic Gardening Solutions
Enfield Produce
Zeolite Australia
