Mixed Drying Loads

Mixing wood of different moisture contents in the same kiln load causes big problems, but mixing different lumber species at the same moisture content can be okay. May 15, 2012

Question
We filled our solar kiln today with some ash and walnut. The wood has been air drying for about 6 months. We have some walnut logs to cut, but are not sure if we should put this in the kiln to fill it up. We do have some air dry lumber that we could put in it, but it's in a different place and we would have to go pick it up.

Forum Responses
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Generally, never mic MCs. So, do not put the green walnut in with the other material.

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From contributor A:
If you put the green wood in with the dry wood, the dry wood will suck up the moisture from the green wood. You will get checking like mad. There is no way to control the exchange of moisture. Mixing the walnut and ash is not the problem so long as they are about the same MC and chances are if they have been air drying 6 months, they should be around 18% MC.