Introduction

Add style to your deck by building planter boxes to sit on top of the railing. This is a great project for a beginner woodworker.
Cut and Assemble Boards
Determine the size of the planter box. It is best to use pressure-treated wood or cedar.
Cut the side and end pieces to the size you want. Then fasten them together using galvanized screws. Measure the box's inside length and width. Cut a piece to fit in the bottom. Secure the bottom through the sides with galvanized screws.
Step 1

Add Cleats and Drill Drainage Holes
Attach cleats to the bottom of the box. This will give you a nice profile and keep the box from damaging the railing over time.
Drill three or four drainage holes in the bottom of the box.
Step 2

Cut and Insert a Liner
Cut a piece of vinyl or nylon screen to fit into the bottom of the box. The screen will help hold gravel and dirt in the box.
Step 3
Attach to the Deck
You can screw the box directly to your deck railing. Another option is to use a store-bought bracket system that attaches to the side of the railing.