How To Build A Raised Garden Box With Trex

This free workbench plans provides detailed instructions for building a simple, functional, and beautiful raised garden box with Trex. It might be an alternative to using traditional concrete blocks or bricks in your backyard. Whether you’re a beginner or advanced builder, this project will come together easily and quickly with a good set of basic hand tools and materials that you probably already have around the house. Start by measuring and drawing out your layout on paper before turning these plans into reality.

This raised garden box from TREX is easy to assemble and can be assembled without any power tools. Made of high-quality, sustainable materials, this garden box is durable and long-lasting.

You may have seen some of the beautiful garden boxes made with Trex decking on social media or in friends’ yards. If you’ve ever wondered how to make one, I’m here to tell you it’s easier than you think! When done correctly, the finished box will be durable enough to last for years, and it will look great doing it. Here’s what you’ll need:

You Will Need:

You will need:

  • Trex composite lumber (Click here to see our full range of Trex products.)
  • 8 x 12” x 16” boards – 2 (one for each end of box)
  • 8 x 8” x 16” boards – 4 (two for each side of box)
  • Wood screws – 3/4″ or 1″ depending on your application. We recommend using galvanized decking screws instead of nails to avoid corrosion from rainwater. You’ll need around 100 screws that are 2-3″ long, but it’s best to buy an extra dozen just in case! You also might want some shorter ones for attaching bottom panel if yours doesn’t come pre-attached. Also, make sure you have both flat head and pan head screws so you can choose which looks better based on the orientation of your boards when they’re laid out flat.

1. Trex Transcend Fascia

Trex Transcend Fascia is a composite material that can be used in a variety of ways. It’s strong and durable, making it ideal for raised garden boxes. The product comes in a variety of colors, so you can choose what best suits your home’s aesthetics. Trex Transcend Fascia is easy to install as well.

2. 2×4 Pressure-Treated Lumber

2×4 PT Lumber is a common size of lumber that you’ll find in most hardware stores. It’s also known as 2-by-4 or 2×4, and it’s often used for framing houses. PT stands for pressure treated lumber, which means that the wood has been treated with chemicals that make it last longer than untreated lumber (or at least prevent termites or other pests from eating away at the wood).

PT can be made from any type of tree and comes in many different lengths depending on what you are using it for. Common sizes are 4′ long boards (which is how I’ve built my raised garden bed), 6′ long boards and 12′ long boards if you need more length than that all depends on what size box your building.

3. 4×4 Pressure-Treated Lumber

  • You need a length of 4×4 pressure-treated lumber (also known as timbers) that is 9 feet long. Cut the timber down to 8 feet and make sure the ends are square, or 90-degree angles.
  • Use a power saw to cut two more pieces from your 4×4 timber at 2 feet each. These pieces will support the top rails for your raised garden box.
  • Lay one of your treated 4x4s on its side on your work surface with its flat end facing upwards, then align one of your shorter timbers horizontally across it so that every inch overlaps by half an inch (1/2”). Repeat this process with another pair of shorter timbers lined up with the first ones so they form two sets of four smaller sections running across each other at right angles—you should now have eight smaller sections remaining on top of one longer piece that extends along both sides and down into these overlapping areas where they meet in a cross pattern off center by 1/2”

4. 2 1/2 inch Exterior Grade Screws

To build a raised garden box with Trex, you will need 2 1/2 inch exterior grade screws. These screws are strong and durable and the right size for this project.

5. Landscape Fabric Staples

  • Use a hammer to pound in the staples.
  • Use a staple gun to secure the fabric to the wood.
  • Make sure the staples are driven in at an angle, just like you’d do with a nail or a screw! The more surface area they’re covering, the more effective they’ll be as support for your plants.
  • Cover all sides of your boxes with landscape fabric (including top and bottom) to make it look nice and neat when viewed from above, but also so that weeds aren’t able to grow through from below.

6. Landscape Fabric, Minimum 36-inch Width

You can choose from a variety of landscape fabrics, but I recommend staying away from plastic sheeting and other synthetic materials. They can trap water and heat, which can lead to mold issues or even structural failure in your raised garden box. Instead, I recommend laying down a layer of organic fabric such as burlap or jute. This material will help prevent weeds from growing in the soil while also allowing the garden’s roots to breathe through it easily. Landscape fabric is relatively inexpensive (you can buy enough for about $15) and easy to install—it comes rolled up on a roll so all you have to do is unroll it over top of the soil in your raised garden box.

7. Raised Garden Bed Soil Mix

For the soil mix, you’ll need to start with 1/3 compost and 2/3 soil. If you don’t have compost on hand, it can be purchased at your local garden center. The type of soil is up to you, but if you have clay or silt in your backyard already, mix in some sand before adding the compost. The sand will help provide good drainage for the plants when they go into their new homes later on.

If you want to make your own soil mix, try combining equal parts of peat moss and vermiculite (don’t forget about drainage here!). This will give plants a nice boost while also improving their overall health with natural nutrients like nitrogen and phosphorous as well as carbon dioxide for photosynthesis.

Building a raised garden box with Trex material is easier than you might think.

Building a raised garden box with Trex material is easier than you might think! Although these plans are designed for building a 4-foot by 8-foot raised bed, they can easily be modified to fit your needs.

The first step to building your raised bed is finding the right materials. You’ll need:

  • A Trex 2×4 pressure-treated wood post (we used 10)
  • Trex 1/2 in x 4 ft x 8 ft boards (we used 12 of them)

Final words

So if you’re feeling ambitious and want to try your hand at creating your own garden box, take a look at these tips and tricks. You’ll be on your way to growing flowers (or vegetables) in no time.

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