For a garden to flourish, living soil is imperative - and at its core is mycorrhizal fungus. This symbiotic fungus plays a significant part in the well-being and growth of plants, which we'll delve into in this article, discussing its importance and providing practical tips for cultivating it in your own garden.
What is Mycorrhizal Fungus?
Mycorrhizal fungus is a type of fungus that partners with plant roots. This fungus colonizes the roots and creates a network of hyphae, which are thin, filament-like structures. This network broadens the surface area of the roots, allowing plants to absorb more water and nutrients from the soil.
A Quick Guide to the Different Types of Mycorrhizal Fungi
Most gardeners don’t realise there isn’t just one type of mycorrhizal fungus working in your soil. Different fungi form different partnerships with different plants, and knowing the main types helps you work with your garden, not against it.
The two most common kinds you’ll meet in Aussie gardens are:
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Endomycorrhizae (also called arbuscular mycorrhizae): These fungi push tiny hyphae right into the plant’s root cells. They’re the most widespread type and team up with vegetables, herbs, annuals and many ornamentals.
- Ectomycorrhizae: These wrap around the outside of roots instead of growing inside. They’re especially common on trees like eucalypts and pines.
Both work towards the same goal — expanding the root’s reach into the soil, helping your plants find water and nutrients more easily. Knowing which type your plants favour can help you tailor your soil care for better results.
Mycorrhizae and Australian Plants
Here in Australia, mycorrhizal fungi form partnerships with many native plants right in our own backyards — from wattles to banksias. These fungi are especially important in Aussie soils, where nutrients like phosphorus can be locked up or hard to access.
Some native orchids and other bush plants depend heavily on these fungal connections to survive and thrive, especially in nutrient-poor soils. Encouraging mycorrhizal growth in your garden soil not only helps your veggies and ornamentals perform better, it also supports the broader soil web that native plants have evolved with.
Think of It Like a “Wood Wide Web”
You might have heard gardeners talk about the underground “Wood Wide Web” — and there’s truth behind the nickname. Mycorrhizal fungi act like tiny soil cables linking roots of different plants together. This network allows plants to share resources and chemical signals with each other. It’s not just nerdy soil biology talk — it’s a real part of how plants support each other in a healthy garden.
The stronger and more connected this fungal web is, the better your plants can weather drought, fend off disease and make the most of whatever nutrients are available. It’s a beautiful reminder that a garden isn’t just plants in dirt — it’s a living, interconnected ecosystem.
The Advantages of Mycorrhizal Fungus
The mycorrhizal fungus offers numerous benefits to plants, such as:
- Enhancing Nutrient Absorption: The hyphae network generated by the mycorrhizal fungus expands the surface area of roots, allowing plants to better absorb water and nutrients from the soil.
- Strengthening Soil Structure: The mycorrhizal fungus breaks down organic matter, strengthening soil structure and aggregation. It does this by producing a glycoprotein called glomalin, which acts as a binding agent, improving soil structure and increasing its ability to retain water and nutrients. Want to learn more about glomalin? Click here to start : Understanding Glomalin: The Secret to Soil Health and Plant Growth
- Boosting Stress Tolerance: Plants with mycorrhizal fungus have been found to be more resilient to stress caused by drought, extreme temperatures, and disease.
- Fostering Biodiversity: Mycorrhizal fungus contributes to soil biodiversity by supporting a diverse population of microorganisms, insects, and other life forms.
If It Doesn’t Seem to Be Helping — Here’s Why
Even when you do everything right, you might wonder why your mycorrhizal fungi don’t seem to be kicking goals straight away. A few common hiccups include:
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Too much soil disturbance: Deep cultivation or turning soil over can break up fungal networks before they’re well-established.
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Sterile potting mixes: Fresh, completely sterile mixes don’t have existing fungi — and until something colonises them, there’s nothing for plants to partner with.
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High soluble phosphorus: Very high phosphorus levels from fertilisers can reduce a plant’s need to partner with fungi, slowing colonisation.
- Soil around roots not inviting: If roots never touch the hyphae (for example, when inoculants are spread on the soil surface only), the partnership never gets started.
Understanding these common roadblocks helps you adjust your garden practice and get the most out of your soil biology.
Growing Mycorrhizal Fungus in Your Garden
Encouraging the growth of mycorrhizal fungus in your garden is key to the health and growth of your plants. Follow these tips for promoting mycorrhizal fungus:
- Add Organic Material: Adding organic material such as compost or decomposed manure nourishes mycorrhizal fungus and other soil microorganisms.
- Minimize Chemical Usage: Chemical products like pesticides and fertilizers can be harmful to mycorrhizal fungus, so limit their use in the garden.
- Plant a Variety of Plants: A diverse range of plants nurtures soil biodiversity and encourages mycorrhizal fungus growth.
- Moderate Watering: Over-watering can harm mycorrhizal fungus, so water your plants only when the soil is dry.
- Use Fertilizers Carefully: Over-fertilizing can also be harmful to mycorrhizal fungus, so use fertilizers wisely and only as needed.
How to Give Mycorrhizae a Head Start
If you’re using a mycorrhizal inoculant in your garden — like our Root Roids or similar products — here’s how to make sure those tiny fungal helpers hit the ground running:
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Make contact with the roots: When transplanting seedlings or young plants, dust inoculant around the root ball or dip the roots lightly before planting. That direct contact early on makes all the difference.
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Mix it into potting media: If you’re potting up, work the inoculant lightly into the soil around where the roots will grow.
- Water-in gently: After applying, follow with a light watering to help the spores settle into the soil.
Remember, these fungi don’t work like fertiliser — they don’t offer instant results you can see in a day. Instead, over weeks and months you’ll notice plants that access nutrients more efficiently, resist dry spells better and grow with deeper, healthier roots.
Why Mycorrhizae Matter More Than Ever in 2026
As gardeners in 2026, we’re facing hotter summers, drier spells and more unpredictable rainfall than ever before. It’s not just about greener lawns — it’s about building resilience into our gardens.
Mycorrhizal fungi are one of nature’s ways of doing that. By helping roots forage deeper and more efficiently, these fungi make plants better equipped to cope with stress, whether from heat, drought or poor soil conditions. Encouraging a healthy fungal network in your garden soil improves water retention, nutrient access and the overall strength of your plants. That’s a win for your paddock tomatoes, your citrus grove and the local native patch out the back.
Real Benefits Backed by Science & Experience
Garden science and hands-on experience agree — mycorrhizal associations improve plant health and soil structure. Research shows these fungi extend the soil volume plants can explore, make phosphorus and other nutrients easier for roots to access, and increase resilience to stress when healthy soil biology is encouraged. Our own growers report stronger root systems and more vigorous plants when they nurture these natural networks.
This isn’t just theory — it’s what happens in thriving soil ecosystems wherever microbes and roots work together.
In conclusion
Mycorrhizal fungus is an integral part of living soil, playing a crucial role in the growth and health of plants. By promoting its growth in your garden, you can enhance soil structure, increase plant resilience, and foster biodiversity in the soil. Make sure to add organic material, minimize chemical use, plant a variety of plants, and practice moderate watering and fertilizing. With time and effort, you'll have a thriving garden teeming with healthy plants.
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