Fill the bottom two inches of the barrel with Styrofoam packing peanuts (a good way to reuse them), which will help with drainage and make the planter a bit lighter should you ever decide to move it.
Add about two cubic feet of potting soil (not regular garden soil) on top of the peanuts. Potting soil contains pumice and other materials that encourage water drainage.
Although most plants will climb any type of structure, Hulbert warns that some plants, namely sweet peas, need a more delicate frame to climb. For these plants, run thin wire or cotton twine around the outside of the tripod at even intervals to form ladderlike rungs. Secure each rung by wrapping the twine around each tripod leg or by attaching the twine to each leg with a small nail.
Settle your climbing plants in the container first (see "What to Plant" right), followed by ground cover that will spill over the edges of the barrel. Then watch your barrel become a blooming, eye-catching addition to your garden or patio with nary a lattice in sight.