How To Build A Planter Box Using Decking

Building a planter box from decking is a great way to create a functional and attractive feature for your garden or patio area. This method will make use of prefabricated decking and railings that serve as the box’s base and sides. There are several advantages to using this kind of lumber for building a planter box. The first is that it makes use of lumber that’s probably already on site and ready to use; it also means there are no ends to cut or jointed boards involved in the whole process. Another advantage is that prefabricated pieces like this don’t require much maintenance which means less upkeep for you. Building a planter box using decking is a great way to maximize your garden space without taking up too much room in your backyard. A planter box can be built from a variety of materials, but the material you choose will depend on the style and size you are looking for. This how-to guide will walk you through everything you need to know to build your own planter box using decking.

You’ve got a new deck and you bought some lovely, exotic plants to put in pots on top of it. But wait! You can’t just put the pot on the deck, or even put it directly on the ground. What to do? Use your leftover board, of course! Here’s how to build a planter box that fits seamlessly along your deck railing:

Step 1: Cut your planter pieces.

You’ll need to cut your 2x4s to length, width and height. For example: You want the planter box to be 4 feet long and 2 feet wide.

Measure the length of each side of your decking board (4 feet) and use that measurement as a guide for how long you should cut your 2x4s.

For this example, if we are building a planter box that is 4 feet by 2 feet and we’re using 1″ thick cedar deck boards, we’d need two 8-foot lengths of 1″ thick cedar decking material (14″ x 7″).

Next step will be cutting those pieces into three equal segments so they measure 3′ 6″, 3′ 4″, and 3′ 0″.

The vertical pieces will also be cut at 90 degree angles so that when laid out flat on their sides they form an X shape with no gaps between them – this makes for easy assembly later on down the road.

Step 2: Place bottom piece on the box & mark around it.

Cut the bottom piece in half. Place one of the pieces inside the box and make sure it fits snugly, without any gaps or bulges.

If you’re using a plastic or metal edger, this part is especially important because those materials expand when they get hot—which means if there’s any extra space in between your planter box and bottom piece, it could cause problems later on when you put soil into the container. Make sure to check before adding soil because once it gets wet, removing excess concrete becomes much more difficult.

  • Make sure that your bottom piece is level (parallel with ground surface) at all four corners. If not, tap down as needed until even across all corners. A spirit level can help here!
  • Check that everything looks straight by flipping over onto its side; do any edges look like they slant? If so try repositioning them so that they are straight up and down again – away from being bowed upward toward center or leaning toward outside edge (this may mean readjusting how deep each corner cutout has been made). This will ensure that no water pools underneath where plants’ roots might rot away due to being trapped within trapped moisture pocket created by sagging sides collapsing down onto themselves causing dampness buildup during rainy seasons which can lead towards root rot problems later on if left unchecked for too long without proper drainage holes installed first then followed soon afterwards by proper watering habits established from day 1 onward after construction is completed successfully following completion day 1 then 2nd day building days thereafter before planting seeds/plants into containers filled with potting mix combined with fertilizer pellets added prior before placing into garden beds outdoors where sun shines brightly throughout entire day hours so crops grow quickly under conditions optimal ideal temperature.

Step 3: Screw bottom to the side pieces from inside of planter using 1-5/8″ exterior wood screws.

  • Screw bottom to the side pieces from inside of planter using 1-5/8″ exterior wood screws. Pre-drill holes in the bottom of the planter, then screw in place from inside with a drill and screwdriver
  • Lay weed block inside planter box and secure with staples every 6” along its length
  • Place outside trim on top of box, nail on bottom of trim with 1-1/4″ finish nails

Step 4: Pre-drill two holes in each end of boards for top trim.

Now that you’ve pre-drilled the holes for the trim, it’s time to add it.

  • Pre-drill two holes in each end of boards for top trim.
  • Attach top trim with 1″ deck screws or nail gun, depending on preference and availability of tools available to you at home or work location (if they’re not available at a hardware store). Make sure your nails hit the side of box and not directly through middle board, as this could weaken structure in future years when moisture builds up inside long enough to cause warping damage on an otherwise well-built planter box.
  • Finish off with decorative end caps if desired.

Step 5: Attach Trim – Lay trim board against planter with overhang on outside.

  • Attach trim board to planter with 1-1/4″ finish nails. Start at one end of your planter box, and run a line of finish nails along the outside edge of your trim board. Repeat this process on each side of the planter box.
  • Make sure that your overhang is about 1/4″ past the inside edge of your box and also make sure that it is flush with the top edge of your decking boards.

Step 6: Nail trim board to the side of planter with 1-1/4″ finish nails. Repeat this process on each end.

  • Nail trim board to the side of planter with 1-1/4″ finish nails. Repeat this process on each end. Use a level to make sure the trims are straight and flush with the planter box before nailing them in place, then use your nail gun to drive the nails into the woodsplit pallet ends and fence boards.

Step 7: Line Planter with Weed Blocker – Cut weed blocker to fit inside box and place inside.

To prevent weeds from growing in your planter box, you need to line the inside with a weed blocker. We used a piece of fabric cut to size and then placed it into our box. This will help keep any weeds that may be present from getting through the floorboards, while also allowing water and nutrients to reach your plants through the holes in the bottom board.

The planter box you’ve made is lovely, but so is your deck railing.

The planter box you’ve made is lovely, but so is your deck railing! Decking is a great material for making planter boxes because it’s easy to work with and durable. It can be cut into any shape or size and installed in many different ways. You can go with straight boards to create a simple box or you can use the same wood to build a more elaborate design that matches the rest of your decking. If you’re looking for something unique, consider using different woods for each side of the planter box—that way, no matter which side of the railing faces forward (or back), there will always be something interesting about it from an aesthetic perspective.

You might also want to consider using coordinating colors on either end of your planter boxes as well—this will help keep them consistent throughout while also adding color variety between two sides facing outwards instead just one at once.

Final words

You’ve created a planter box! You can now plant almost anything you’d like and expect a long-lasting planter. Don’t like the color of your box? Use paint to add some flair. Not only does this create an even more beautiful flower garden, but it also adds variety

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