Yes, you can make a retaining wall out of wood, but it is not recommended. A wooden retaining wall might not be strong enough to hold the soil in place and could eventually collapse.

Yes, you can make a retaining wall out of wood. You just need to make sure that the wood is properly treated so that it will be resistant to moisture and decay. Cedar or redwood are great choices for a retaining wall because they are both naturally resistant to decay, and they will also weather well if left untreated.