Australia’s hottest months can be unforgiving – not just for farmers, but for stored grain too. High temperatures, humidity, and pest pressure can all threaten your hard-earned crop. If conditions aren’t managed properly, it can lead to mould, insect infestations, or even spontaneous combustion in silos.
In this guide, we’ll walk through the most effective ways to store grain safely during summer, based on practical experience, proven methods, and best-practice recommendations from Australian sources like GRDC and AgVic.
Grain is a living organism. Even after harvest, it continues to respire. In hot conditions, this respiration accelerates, creating heat and moisture – perfect conditions for mould and insects. If left unchecked, this can lower grain quality, impact germination, and reduce your selling price or usability.
The good news: With the right prep, tools, and monitoring, you can keep your grain safe and high quality, even in the peak of summer.
Before bringing in new grain, thoroughly clean out silos, augers, headers, and storage areas. Remove all old grain, dust, and chaff – this is where pests and fungi love to hide.
Tip: Dust and residue can harbour grain pests like the lesser grain borer and rust-red flour beetle. A clean start is the best defence.
Once cleaned, treat internal surfaces with protectants to reduce pest pressure. Products containing spinosad, s-methoprene, deltamethrin, or diatomaceous earth (DE) can be applied to floors and walls of silos or sheds.
If using chemical protectants, check withholding periods and compliance with your grain buyer’s MRL (maximum residue limit) requirements.
Best for: Long-term storage, fumigation capability, minimal pest risk
Sealed silos maintain a stable environment and can hold fumigant gases if needed. They’re also ideal for aeration cooling, which we’ll cover below.
To qualify as gas-tight, silos should:
Best for: Short- to medium-term storage on-farm, especially for overflow
Grain bags are flexible and affordable, but they’re not as robust as silos. They should be:
Don’t store bags near paddock edges – kangaroos and rodents are regular offenders when it comes to tearing holes in silage and grain bags.
Aeration is critical for keeping grain safe in summer. Cool, dry grain is much less likely to spoil or attract pests.
Ideal temperature ranges:
Use aeration fans to push ambient air through the silo:
Lower grain temperatures reduce insect activity and slow mould growth. Cooling to 15°C can also reduce fumigation needs later.
Temperature, moisture, and pest levels should be monitored weekly in the first month of storage, then monthly after.
Use:
Set thresholds for action. For example, if temperature rises >30°C or moisture increases by 1 – 2%, investigate immediately.
If pests are detected and aeration alone isn’t effective, fumigation may be needed.
Options:
Never fumigate in unsealed silos. Gas will escape before it’s effective – and you risk residues and pest resistance.
After fumigation (or during harvest), you can treat grain with registered protectants to provide longer-term insect resistance.
Common active ingredients:
Always check that your protectants are registered for the crop type and storage method you’re using.
Rotating grain or blending batches from different areas of the silo can even out moisture and temperature differences.
Storing grain safely through an Australian summer isn’t easy, but it’s absolutely achievable. With the right preparation, good hygiene, and regular monitoring, you can protect your harvest and maximise your return.
Every tonne of grain you protect from damage is money back in your pocket, and confidence that your product will meet the market’s expectations when it’s time to sell.