Treated posts are chemically pressure-treated to reduce rot and decay and are often less expensive than cedar posts. Treated posts have a slightly green tint initially and can be left natural or painted once they dry out (after about 6 months). They can last 20-30 years.
Cedar Posts vs. Treated Posts
Cedar posts are highly resistant to insect damage and decay but are usually more expensive than pressure-treated posts, Cedar posts can be left natural or painted soon after installation. A cedar post should last 15 to 20 years.