Seasoned vs Green Firewood: How to Tell the Difference Before You Buy

Short version: seasoned firewood has had the moisture content drop through drying time and exposure to air, typically to somewhere under 20 percent, while green (freshly cut) wood can sit well above that, sometimes north of 40 to 50 percent depending on species. Burning green wood wastes most of its energy boiling off water instead of heating your house, cakes your flue with creosote, and is a genuine chimney fire risk over a season of use. The good news is that telling the two apart does not require trade experience. A $20 moisture meter and a few simple checks will catch almost every case of green wood sold as seasoned.

Why this actually matters, not just for comfort

Wood is mostly cellulose, water and a bit of everything else. Freshly felled hardwood can be as much as half water by weight. Every bit of that water has to boil off before the wood itself starts burning properly, which means green wood on the fire spends a large share of its heat output just drying itself out rather than warming the room. Beyond the wasted heat, the incomplete combustion that comes with burning wet wood produces more smoke and more creosote, which condenses in a cooler flue and builds up as a hard, flammable residue. A heater running on green wood for a season is a heater that needs its flue swept more urgently than one running properly seasoned wood.

This is also, bluntly, where a fair few firewood complaints come from. Wood cut and split this year, sold as "seasoned" because it looks dry on the outside, is one of the most common ways buyers get short-changed, sometimes through genuine seller confusion about what seasoned means, sometimes not.

The moisture meter test (the reliable one)

A basic pin-type moisture meter costs very little and removes almost all the guesswork. To use one properly:

1. Split a piece open. Always test the freshly exposed inside face, not the weathered outer surface, which dries faster than the core and will give you an artificially low reading.
2. Press the pins into the fresh split face, ideally in from the end grain a little rather than right at the tip.
3. Read the percentage. Under 20 percent is good, ready-to-burn seasoned wood for most species. 20 to 25 percent will burn but is not ideal. Above 25 to 30 percent is green or under-seasoned, and the seller's "seasoned" claim does not hold up.

Test a handful of pieces from different parts of the load, not just one, because a stack can be genuinely mixed if it was cut over different periods.

The checks that work without a meter

If you turn up to buy wood without a meter, these give you a reasonable read:

• The knock test. Two seasoned pieces knocked together give a sharp, hollow, almost cracking sound. Green wood gives a duller, flatter thud, because the extra water dampens the resonance. It is subtle at first but easy to learn after a few comparisons.
• Weight. Pick up a piece. Green wood of the same size is noticeably heavier than seasoned wood of the same species, again because of the water content.
• Colour and end checks. Seasoned splits typically show darker, greyed ends with visible radial cracks (checking) spreading out from the centre where the wood has dried and shrunk. Freshly cut ends look pale, almost wet, and rarely show that cracking pattern yet.
• Bark. Bark on well-seasoned wood is often loose or starting to separate. Bark that is still tight and fresh-looking is a sign the wood has not been drying long.
• Smell. Green wood, especially eucalypt species, often has a stronger, sappier smell than dried wood. Not scientific, but a useful extra data point.
• Burn behaviour, if you can test a piece. Green wood hisses, spits and struggles to hold a flame, sometimes bubbling sap at the ends. Seasoned wood catches and burns steadily.

How long does seasoning actually take

This varies a lot by species, split size and how the wood was stored, so treat any number as indicative rather than a guarantee. As a general rule, most common Australian hardwood species need somewhere in the order of six months to a full year split and stacked in a dry, airy spot to season properly, and dense species can take longer. Wood stacked in full rounds rather than split, or stored somewhere damp and unventilated, seasons far more slowly, sometimes barely at all, no matter how long it has technically been sitting there. "Cut two years ago" is not the same claim as "split and stacked in the open for two years," and it is worth asking which one you are being told.

What to do if you've bought green wood as seasoned

Raise it with the seller with your moisture readings in hand, most reasonable sellers will make it right, whether that is a partial refund, a swap, or an acknowledgment for future orders. If you are stuck with a load of green wood, the practical fix is to split it smaller (smaller pieces season faster), stack it under cover with good airflow on the sides, and burn last season's properly seasoned wood in the meantime if you have any.

Buying with confidence

Species matters here too. Some of Australia's best-known firewood species season and burn differently from each other, and it helps to know what you are buying before you judge it by these tests. Our rundown of the best firewood species in Australia covers density, burn time and coaling qualities species by species. And if the load you are looking at has travelled any real distance, particularly across a state or biosecurity zone line, check our guide to firewood biosecurity and moving timber before you commit.

When you are ready to buy, browse firewood listings and ask sellers directly for a moisture reading or a knock test on collection, most will happily oblige, and a seller who hesitates has told you something useful. Selling your own well-seasoned wood, list it free and mention the moisture content and seasoning time in the ad; buyers who know what to look for will trust the listing more for it.