Building a great fire starts long before you strike the match. A great fire is built with high quality, well, seasoned firewood. Well seasoned firewood will have a moisture content under 20%. Firewood with moisture contents higher than that can be difficult to work with and increase the rate that creosote deposits in your chimney. So how do you get seasoned firewood?
One way is to buy it from a reputable firewood dealer. But buyer beware! Firewood that has sat for a “season” may not necessarily be dry. Some species dry at a slower rate than others. For example, hardwoods (oak, ash) dry slower than softwoods (pine, spruce). And some don’t dry very well at all until split. Birch has a water-tight bark that doesn’t breathe well. When you buy from a firewood dealer, ask when the wood was cut and when it was split to get a handle on the level of seasoning that has occurred. If your firewood dealer has a moisture metre, you can also ask for a moisture content reading. Make sure they take it from several sample pieces though!
The rate that your firewood will season will depend a lot on what the weather conditions are. It stands to reason that firewood will dry faster when temperatures are hot and humidity is low, and will dry slowly when temperatures are cool and humidity is high. Firewood will still dry in freezing temperatures as long as humidity is not too high. As mentioned before wood species will also influence the rate at which seasoning will take. How long you need will also be influenced by the date that the trees were felled, and the date that they were split. Your firewood dealer may have started the process for you and you only need to finish it. Ideally, give yourself a year to properly season your firewood. At the very least 2 to 4 months during a hot dry time of year.
The second key ingredient to seasoning your own firewood is to store it so it has optimal drying conditions. A garage or closed shed is a good place to store your firewood if it has already been seasoned, but not before! Humidity levels are too high in these structures and the air flow required for drying is minimal to non-existent. Once your wood is seasoned, store it in a shed or garage to keep the precipitation off.
To season your firewood, get it off the ground, make sure it has airflow all around, and protect the top of the pile from precipitation. A three-sided lean-to style woodshed with slatted sides facing south is an ideal place to season your firewood. If you don’t want to invest in a shed, stacking your firewood on treated 2x4s is enough to get it off the ground. Remember when stacking, the wood will shrink and shift somewhat so make sure the pile is stable by stacking the ends perpendicular to the middle wood, or use 2x4s on the ends to brace the stack. If you are stacking multiple rows, stack in a north-south direction if feasible for your yard, and leave a foot or two in between stacks to maximize exposure to the sun and airflow. The top can be covered with a plywood sheet or tarp, but make sure to leave the sides exposed.
In summary, well-seasoned firewood = time + proper storage!