Fence issue

[jake12345]

hey guys so ive recentley started building this fence and realised my posts are h3 not h4 .. i was wondering how long do youse think it will take the h3 to rott and what would be the best way to get around this issue . ie cut posts of at bottom rail to keep top half of fence and then dig posts in the ground out lay concrete pads and attach stirups to pads and fence to stirups .?
any suggestions would be muchley appreciated

 

[zimmy1948]

Here's what I do when burying any kind of posts even pressure treated. I get a can of roof coating one gallon can and use a putty knife and cover the bottom and up as far as the dirt or concrete will cover. been doing it for years. I use a old paint brush to smooth it out.