Measure the distance between two bulbs on an outdoor twinkle light strand. Mark the sides of a planter with dots separated by the same distance as the bulbs. Place the marks wherever you wish to add a light, such as around the top rim, along the corners or to cover the face of each side.
Drill 1/4-inch-diameter holes through each mark. The drill bit should be suitable for the planter material. For example, use a ceramic drill bit to make holes through terra cotta or glazed ceramic planters.
Insert the bulbs through the holes from the inside of the planter. The bulbs will be visible, but the wires will not. Cover each hole on the inside of the planter with duct tape. Duct tape is waterproof and will act as a seal for the holes so dirt and water won't escape from the planter.
Drape the power cord over the back side of the planter.
Add the twinkle lights to a liner, wooden planter as described in Section 1. Measure the dimensions of each side of a wooden linear planter. Purchase acrylic sheets and have them cut to size at the home improvement store. Acrylic sheets are available in a variety of colors and make decorative covers for the lights on square and rectangular wood planters.
Remove the front bolts from 3/4-inch-long acrylic wall mounts. Install the base of a wall mount at each corner of the planter. Wall mounts attach the acrylic sheet to the planter without crushing the lights.
Position each sheet of acrylic against the sides of the planter, one at a time. Mark the points where the wall mounts touch the acrylic. Drill 1/4-inch holes through the marks.
Fit the holes over the wall mounts and attach the acrylic using the front bolts for each wall mount. Follow the process to add acrylic sheets to all four sides of the planter. The lights cast a glow through the colored acrylic.