Learning how to season firewood at home saves you a winter of smoky, sulking fires. Seasoned logs light faster, burn hotter and produce much less soot, but only once they have dried properly. 

Key takeaways: how to season firewood at a glance

• Seasoned firewood has dried to a moisture content of 20% or less on a wet basis, according to HETAS.

• Air drying typically takes 12 to 24 months, according to Forest Research, so start a year or two before you need the logs.

• Split the logs, stack them loosely off the ground in a sunny, breezy spot, and cover the top only.

• A log store should shelter logs from rain while letting air through the stack, and slatted panels allow more airflow than solid ones.

• Split a log, press a moisture meter into the fresh face and test several logs. A reading of 20% or less on a wet basis is ready to burn.

• In England, wood sold in loose volumes under 2 cubic metres must be Ready to Burn certified at 20% or less, according to GOV.UK, while larger loads can arrive wet.

Firstly, what is seasoned firewood?

Seasoned firewood is wood that has dried to a moisture content of 20% or less, the level HETAS gives for burning wood fuel. Freshly felled wood sits well above that. Forest Research puts green wood at around 50 to 60% on a wet basis, and says log stoves and boilers typically need 15 to 25%.

Water is a problem when it comes to burning logs because the fire has to boil it off before the wood gives out useful heat. 

Wet logs light slowly, smoulder and leave more soot and tar in the flue. HETAS links dry wood to more heat per log, much less soot and a lower risk of a chimney fire. Suffolk Trading Standards states that burning wet wood can produce at least twice the smoke of seasoned wood.

Your stove or fire manufacturer's instructions take priority over any general figure, so check them for the moisture limit that applies to your appliance.

Wet basis and dry basis: why a moisture meter may read differently

Moisture content can be measured in two ways, and they give different numbers for the same log. Wet basis compares the weight of the water with the total weight of the wood, water included. Dry basis compares it with the weight of the wood once all the water is removed.

HETAS and Woodsure use wet basis for wood fuel, so a figure of 20% describes a log in which water makes up a fifth of the total weight. HETAS also warns that some meters designed for construction read on a dry basis. A reading of 25% on a dry basis equals 20% on a wet basis.

The table below shows the dry basis reading that matches each wet basis figure:

Why bought logs may need seasoning at home

In England, wood sold in loose volumes under 2 cubic metres must be certified Ready to Burn, which confirms a moisture content of 20% or less, according to GOV.UK. Wood sold in loads of 2 cubic metres or more needs no certification, so a bulk delivery can arrive wet.

Ready to Burn is the government-backed certification scheme for dry firewood, and Woodsure runs it for wood fuel. Certified bags and small loads carry the Ready to Burn logo. 

For loads of 2 cubic metres or more, the UK government requires the supplier to provide a notice explaining how to dry, store and check the moisture of the wood. The certification rules described here apply in England.

Logs from your own trees, or from a tree surgeon's clearance, typically arrive freshly felled and need the full seasoning time.

Looking for logs ready to burn now?

If you would rather not wait, our Ready to Burn logs are certified at 20% moisture or less and can go straight into a store.

How to season logs at home: step by step

To season logs at home, split them to stove length, stack them loosely off the ground where sun and wind reach them, cover only the top, and leave them for a year or more before testing with a moisture meter.

1) Start early: Late spring is the best time to begin and as soon as possible is the next best. Any freshly felled logs left on the ground are prone to mould, rot and insect damage, so collecting and storing these promptly is important for keeping firewood most effective.

2) Cut and split: cut the logs to the length your stove or fire takes, then split them. Splitting exposes more of the wood to the air, which can help to dry it faster. Small splits dry sooner than large rounds.

3) Choose a sunny, breezy spot: HETAS names time, air and sunlight as the three things wood needs to season. An open site gives the logs more of all three than a sheltered corner.

4) Raise the stack: pallets, bearers or a log store base lift the logs clear of damp ground and let air move underneath.

5) Stack loosely: build the stack one row deep where space allows, with gaps between the logs. HETAS advises against putting logs behind other logs, because it reduces airflow and lengthens the drying time.

6) Cover the top only: a roof, sheet or store roof keeps rain off while open sides let air through. Westbeams advises against covering the stack completely.

7) Test, wait and retest: after a year or more, test several logs with a moisture meter. Any that read above 20% go back for more time.

How to season logs in a log store

A log store shelters seasoning logs from rain while letting air move through the stack. A store does not dry wet wood on its own, so airflow, position and time still decide how quickly the logs reach 20%.

HETAS recommends storage that is raised off the ground, lets air circulate and gets plenty of sun through the year. In a ready-made log store, that comes down to a roof, a raised base and sides that let air through.

Solid or slatted log store panels for seasoning logs

Slatted panels leave gaps between the boards so wind passes through the logs. Solid panels block rain driven in sideways but slow the airflow. Westbeams recommends openly vented slats on the sides of any store used for seasoning.

Solid panels suit a very exposed spot where rain blows in from the side. Slatted panels suit a site with moderate exposure, where getting air through the stack is the priority.

Where to put a log store for seasoning

Position decides how much air reaches the logs. Four points apply to any garden:

• Raised base: keep the store clear of damp ground, as HETAS advises for any seasoning stack.

• Open side away from the prevailing wind: this keeps driven rain out of the front, while slatted back and side panels let the wind pass through the logs.

• A gap behind the store: leave room between the back panel and any wall or fence so air can move behind the logs.

• Clear surroundings: cut back plants and long grass that block airflow or hold damp around the base.

Keep drying logs separate from seasoned logs

A drying bay is a section of a store, or a separate store, set aside for logs that have not yet reached 20%. A second bay holds seasoned logs that are ready to burn. Keeping the two apart stops damp logs lying against dry ones, and makes it easy to burn the oldest wood first. We also sell partition panels which make this even easier.

How long does firewood take to season?

Air drying firewood typically takes 12 to 24 months in the UK, according to Forest Research. The time depends on the species, the size of the splits, airflow, the site and the weather.

Air drying, which Forest Research calls passive drying, is the process of leaving logs outdoors so wind and sun remove the moisture without added heat. Forest Research lists the typical moisture content of freshly felled wood, on a wet basis, for six common species:

• Ash: 32% moisture when fresh, the least water to lose of these six woods
• Oak: 47% moisture when fresh, close to half the weight is still water
• European Larch: 50% moisture when fresh, half the weight is water
• Sitka Spruce: 61% moisture when fresh, around 3/5ths of the weight is water
• Poplar: 64% moisture when fresh, just under 2/3rds of the weight is water
• Norway Spruce: 65% moisture when fresh, about 2/3rds of the weight is water

A higher starting figure leaves more water to lose before the logs reach 20%. Species is only one input. Westbeams suggests six to twelve months for lighter softwoods and one to two years for denser hardwoods, and notes that trees felled in winter, before the sap rises, dry sooner than those cut after spring growth begins.

Small splits, an open windy site and a covered top shorten the wait. Large rounds and sheltered corners lengthen it. A calendar can only estimate the finish, so testing with a meter gives the real answer.

How to check the moisture content of firewood

To check the moisture content of firewood, split a log, press the pins of a moisture meter into the freshly split face, and test several logs from different parts of the stack. A reading of 20% or less on a wet basis is ready to burn.

1. Pick several logs: take them from different parts of the stack, including the middle and the bottom, because drying is rarely even.

2. Split each log: the outside of a log dries before its core, so bark or an old cut end can read lower than the wood inside.

3. Press in the pins: push them into the fresh face, following the meter's instructions.

4. Check the settings: HETAS advises setting species and temperature correctly and making sure the meter reads on a wet basis. The wet basis and dry basis explanation covers the difference.

5. Compare with 20%: logs at or below the figure are ready, and logs above it go back for more time before testing again.

Without a meter, Suffolk Trading Standards describes radial cracks in the end grain and bark that comes away easily as signs that wood is ready, while recommending a meter to confirm. Treat those signs as a prompt to test rather than proof.

Planning two winters ahead: how much log store space you need

Plan for two winters at once: one winter's logs drying while the previous winter's supply is burned. Estimate how many logs you burn in a year, then choose either one store with two bays or two smaller stores.

This is a rolling system, and it follows from the drying time. Logs stacked this autumn may not be ready until next winter at best, so the supply you are burning now has to have been stacked a year or more ago.

To estimate your annual use, note how many baskets or barrow loads you burn in a typical week of the heating season. Multiply by the number of weeks you light the fire, then add the same volume again for the supply that is drying.

Common mistakes when seasoning firewood

Seasoning goes wrong in a handful of predictable ways, and each one either slows the drying or produces a misleading reading.

• Stacking on soil or grass: HETAS warns that logs left on the ground are prone to mould, rot and insect damage. Raise the stack on pallets, bearers or a store base.

• Packing the stack tight: logs stacked behind other logs reduce airflow and lengthen drying, according to HETAS. Stack one row deep with gaps where space allows.

• Wrapping the whole stack: a sheet pulled down to the ground traps moisture inside. Cover the top and leave the sides open, as Westbeams advises.

• Pushing a log store against a wall: a store with no gap behind it blocks the air that would move through the back panel. Leave space between the store and any wall or fence.

• Testing unsplit logs or end grain: the surface of a log dries first, so a reading on the outside can understate the moisture inside. Split the log and test the fresh face.

• Expecting a store to do all the work: a store keeps rain off and lets air in, but the logs still need time, a breezy position and a meter check.

• Mixing drying and ready logs: it becomes hard to tell which logs have been tested, and the wrong ones get burned. Keep them in separate bays.

Choose Rutland County Garden Furniture for Log Stores & Logs

Dry logs need a dry, airy place to wait until they are burned, and a supply that runs on a rolling basis needs somewhere to season as well as somewhere to store. 

Our log stores come in a range of sizes, with options for the airflow and shelter your site needs. If you need wood for this winter, shop our hardwood and softwood logs.

• Shop log stores: Find the right size and panel style for seasoning and storing your logs.

• Shop logs: Browse our selection of softwood and hardwood kiln dried logs, available in bulk.

Firewood seasoning FAQs

Can you season firewood in the rain?

Yes, if the stack is covered on top, raised off the ground and open at the sides. Rain falling on the sides evaporates, but a stack wrapped in a sheet or standing on wet ground holds moisture. We would advise protecting seasoning logs from rain and keeping them raised so air can circulate.

Can I speed up how fast firewood seasons?

To speed up the process of seasoning firewood, smaller splits, a single-row stack and a sunny, windy site all shorten the wait. Unfortunately, none removes the need for time!

How can I tell if firewood is wet without a meter?

Wood close to ready tends to show radial cracks in the end grain, loose bark and a lighter weight than freshly cut logs. Suffolk Trading Standards describes cracks and loose bark as signs of dry wood but recommends a meter to confirm, so treat these signs as a prompt to test.