Recommended drying time for lumber

[Meatwad]

I've heard you need to let wood you buy at a place like Home Depot or Lowes dry out for a week or two before use because it can still be drying. Is there a rule of thumb for this or just a general rule for all wood? I swear I've flattened a board and then it twisted on me.

[Tpt life]

Acclimate is the word that should be used. Hardwood floors get delivered two weeks prior to install in my region. 

[wtnhighlander]

The hardwood (oak, poplar, maple or whatever) sold at most home centers is pretty dry. A day or 3 of acclimation is usually enough, at least in my area. But if you try to use construction lumber, be ready to stash it for a month or more.

[Meatwad]

I've got pine and douglas fir. Any good way to tell when it's ready to use? Also it just acclimates in my garage so there's no air conditioning in there.

[wtnhighlander]

Well, you can invest in a moisture meter, but if you have a scale sensitive enough to weigh in ounces or grams, you can take a small board and weigh it every day or so. If the weight stops changing, it has reached equilibrium with the environment. Where I am, that means 10-12%. In the climate-controlled environment of my house, it would drop another 3-4% or so. A friend of mine uses a de-humidifier all the time, and stuff in his house gets below 6%, according to my cheap meter.