How to Make a Barrel Planter? | DIY Steps, Tips & Drawbacks

A barrel planter starts with a used whiskey, wine, or 55-gallon barrel and requires cleaning, drilling drainage holes, securing mesh, and filling with gravel and potting soil.

One afternoon and a few basic tools are all it takes to turn a salvaged barrel into a planter that holds enough soil for tomatoes, small shrubs, or a mixed flower garden. The job is straightforward, but skipping a step — especially drainage or wood treatment — can kill plants within weeks. The steps below cover three barrel types so you can pick the one that matches the weight you can move and the look you want. If you are still deciding between barrel types, our tested roundup of the best barrels for plants breaks down which material and size suits each planting scenario.

Which Barrel Should You Use?

The barrel material decides how much prep work is needed and how long the planter will last. Natural oak wine or whiskey barrels look great but need sealing against rot. Plastic 55-gallon drums are lighter and rot-proof but look industrial. Half-barrels — usually oak — hold roughly 3 to 4 cubic feet of soil and are the most common choice for patios.

How To Prepare A Natural Oak Barrel

This is the classic whiskey- or wine-barrel planter. The natural wood looks good from day one, but it requires more steps than a plastic drum.

Step 1: Clean And Dry

Scrub the inside and outside with warm, soapy water. Rinse thoroughly and let the barrel air-dry completely — any moisture trapped under sealant will speed up rot.

Step 2: Inspect, Sand, And Treat The Wood

Check for soft spots, rot, or leaky seams. Sand rough areas to remove splinters. Apply linseed oil to the exterior for a natural finish, or use a food-safe sealant if you plan to grow herbs or vegetables. Real oak barrels tend to host fungus; spraying the inside and outside with apple cider vinegar inhibits growth before planting.

Step 3: Drill Drainage Holes

Flip the barrel upside down. Mark 4 to 8 evenly spaced spots.

Step 4: Install Mesh Over The Holes

Cut wire mesh or landscape cloth slightly larger than each hole. Staple it in place on the inside of the barrel. Without mesh, soil washes out through the holes after a few rainstorms.

Step 5: Add A Drainage Base

Place 2–3 inches of gravel, small stones, or a broken cinderblock in the bottom of the barrel. Keep this layer separate from the soil — it creates an air gap that lets excess water escape and prevents root rot.

Step 6: Fill With Potting Mix

Use a high-quality potting soil rather than garden dirt, which compacts inside barrels. Leave 2–3 inches of space below the rim to hold water during watering. For a typical half-barrel, expect to use roughly 3 cubic feet of soil — a bag from Home Depot runs about $14.

How To Make A Lightweight Planter Using Expanding Foam

This method from Sika USA cuts the finished weight by roughly half — useful for balconies or decks where moving a soil-filled oak barrel is impractical.

Step 1: Insert PVC Pipes And Seal

Drill holes in the barrel bottom and insert short PVC pipe sections. Seal around each pipe with Sikaflex Construction Sealant to make the joint watertight.

Step 2: Mix And Pour The Foam

Roll the Sika PostFix kit to break the internal seal. Mix for 20 seconds, cut the corner of the bag, and pour the foam into the barrel.

Step 3: Let The Foam Expand And Cure

The foam rises and fills the lower portion of the barrel. Let it cure for 2 hours until fully hardened. Cut the PVC pipes flush with the foam surface.

Step 4: Add Soil And Plants

Once the foam is cured — it is completely safe for plants after curing and does not absorb water — fill the rest of the barrel with potting mix and plant as usual.

Common Barrel Planter Mistakes To Avoid

The top reason barrel planters fail is missing or inadequate drainage. Without holes, water pools at the bottom and roots rot within weeks. The second most common mistake is placing the barrel directly on a wood deck — moisture trapped underneath rots both the barrel and the deck boards. Use casters, bricks, or drain rock to lift the barrel an inch off the surface. A final oversight is using untreated metal bands without priming: rust flakes down into the soil and stains the barrel sides.

Checklist For A Successful Barrel Planter

Run through this list before you start filling with soil.

• Barrel cleaned, dried, and inspected for rot
• Wood treated with linseed oil or food-safe sealant
• 4–8 drainage holes drilled (1-inch diameter)
• Wire mesh or landscape cloth secured over holes
• Gravel or cinderblock layer in bottom for drainage
• Barrel lifted off the ground (casters, bricks, or drain rock)
• High-quality potting mix used, not garden soil
• Rusted metal bands wire-brushed and primed