27/03/2026
⏱ Mineral Minute: Iron
Iron is a small but essential mineral in a living soil system, playing a critical role in plant health and growth.
Even though plants only need iron in trace amounts, its impact is significant.
What Does Iron Do in Plants?
Iron is essential for the production of chlorophyll, the compound that allows plants to convert sunlight into energy.
While iron is not part of chlorophyll itself, it is required for the process that forms it.
This means iron directly supports:
• healthy green leaves
• efficient photosynthesis
• overall plant energy production
Recognising Iron Deficiency
When iron is not available to plants, it often shows up clearly in the leaves.
Common signs include:
• yellowing between the veins (interveinal chlorosis)
• young leaves affected first
• veins remaining green while the rest of the leaf turns pale
This is different from nitrogen deficiency, which usually affects older leaves first.
Iron in the Soil
Iron is usually present in most soils, including sandy soils.
The challenge is not the presence of iron, but its availability to plants.
Iron becomes difficult for plants to access when:
• soil biology is low
• organic matter is lacking
• soil conditions are unbalanced (e.g. high pH)
The Role of Living Soil
In a healthy soil system, microbes help make iron more available to plants.
Certain bacteria and fungi release compounds that unlock iron from the soil, making it easier for plant roots to absorb.
This is another reason why soil biology is just as important as nutrients.
Iron and Sandy Soils
In sandy soils, iron can become less available due to:
• low organic matter
• weak microbial activity
• poor nutrient retention
This can lead to plants showing deficiency symptoms, even when iron is technically present in the soil.
Building Iron Availability Naturally
Instead of adding isolated inputs, iron availability can be improved by building the soil system:
• adding compost and organic matter
• supporting microbial life
• mulching to protect soil conditions
• reducing soil disturbance
Over time, this creates a more stable environment where minerals like iron can cycle naturally.
The Bigger Picture
Iron is a good example of how soil works as a system.
It’s not just about what is in the soil — it’s about what is available, and how biology supports that availability.
When you focus on building living soil, minerals like iron begin to function as part of a balanced, self-sustaining system.
🌱 Healthy soil grows healthy plants.
Follow our page for more posts in the Mineral Minute series, where we break down the key minerals that support soil health and plant growth.
