• 1. Before filling with soil, drill drainage holes in the bottom the size of a quarter. Although the dry wood looks as if no drain holes are needed, the wood slats swell, closing the tiny spaces between them, when the barrel is filled with potting soil and that soil is watered regularly. Without drain holes in the wine barrel's bottom, you risk drowning the roots of plants in the barrel.
• 2. Spray the bottom and inside of the barrel with apple cider vinegar. If your wine barrel is the real thing — solid oak that was used to ferment grapes rather than one purchased at a landscape store— it may play host to a fungus that will grow on the wood. 
• 3. Cut pieces of wire mesh to fit over the drainage holes.
• 4. Secure the mesh with staples if possible.
• 5. Add casters--recommended if your barrel will sit on a patio or deck.

Whether or not to line your barrel with plastic is entirely up to you. Many people feel that a liner significantly extends a barrel’s life — though how much is questionable. One way or another, if your barrel is solid oak, it should last for a good long time.

• You may want to line your barrels for a different reason, which is that it helps the soil to retain moisture. Even large containers can dry out quickly during a stretch of hot summer days. With a liner, you don’t have to water as often.

I hope this is helpful.

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