I think using roofing sealant is the way to go on the inside. For smaller pots I have used spray on 'gutter sealant', which is basically spray on plastic. Someone will probably get excited that theses could be toxic... etc. But if water drains from your roof into your garden then...anyway.

I have stopped getting wine barrels because they really don't last very long and they stop looking nice long before that. Maybe if you got one of those plastic pond liners made to fit inside the barrel. You would still need to keep up with the finish every other year or so. If the barrel wood stays dry, it will shrink and lose the tight barrel look, and the bands may slip (so screw then on); barrels are made to be damp so the wood swells to a tight fit.

I have had them last - untreated with anything - as long as 10 years....maybe longer. Never bothered to time it :-)) And this is up here in the substantially damper PNW!!

I don't think I've gotten more then 3 good years? Oak,is great indoors,terrible outdoors. Its why nobody has oak decking. Also.it may last a freakish long time - IF you never move them. Once a bit of decay sets in..moving them causes ribs to break,loosen.

I would guess the best way to make one last a long time is to use the liners HD sells that fit in an oak barrel to convert them into a pond. If you put plants in them..drill holes in them and the barrel,seal all around with silicon.

I gave mine away to my sister but it's probably 8-10 years old now. The wood was dried but still held dirt. She has succulents in it.

15 to 20 years here. We drill 6 , 3/4" holes in the bottom and prop them up on a couple of 2"x2" to keep them draining well. By the time they rot out the bottom, the plant is so pot bound it is time to chuck it anyway. We have had citrus and dwarf locust and currently icee blue podocarpus in our barrels. I like the aged look of weathered oak. Oh, and I think Stanofh means "silicone" with an "e". It is the stinky waterproof sealant you use in your shower or kitchen sink.

-Babka

wouldn’t you know ..he dug up an old post too

Just to be clear the "He dug up"..is not me. It was somebody else and that post was deleted by the houzz administrator or some title.

it was a post after Babka and before gardengal