How to Build a Planter Box

It’s the season to give your garden an uplift, ready for all the social events and unwinding you’ll be doing outdoors this Spring and Summer. Because of this, there’s no better time to explore ways you can enhance the appearance of your outdoors for you and everybody else to enjoy.

Today, our experts are here to guide you on how to build a planter box, an affordable and effective way to display your flowers and brighten your garden space.

Useful links

Planter boxes, also known as flower boxes, are a container that houses an array of plants and flowers.
Before adding compost to a planter box, install a layer of garden wire fencing across the base of your box and add some landscape fabric on top for drainage.
Wild flowers like cornflowers and cowslip plug plants can co-exist in gardens.

What is a planter box?

Planter boxes, also known as flower boxes, are a container that houses an array of plants and flowers; typically used as a decorative piece in a garden. Planters can also be used to grow your very own veggie garden.

Building your planter box

See below for how to successfully build a planter box, as well as what you’ll need to get the job done right.

Using a tape measure, work out how big you’d like your planter box to be and mark your cut lines accordingly. You’ll need x8 long planks for each side and x8 shorter planks for each end. Using a handsaw, saw your planks to size using your guidelines.

Don’t forget, you’ll also need planks to build the base of your planter box, as well as some extra pieces to add support at the end. If you want your planter box raised, you’ll also need further wood to build the supporting frame.

Once you’re happy with your wood cuts, add a coat of varnish to all sides of each piece for protection against the elements. We recommend using a paint roller to apply your varnish as this’ll prevent any brush marks from appearing. Leave the varnish to completely dry before moving onto the next step.

Starting with the longer planks, assemble them vertically before drilling your shorter planks to the longer ones at both ends using outdoor screws. If you’re building a frame, drill the longer planks into the frame instead. You should repeat this process for the other side of the box before assembling the two sides together.

As the garden planter box will be holding a lot of weight, it’s best to add some supporting planks to each side of your box to help it hold its shape. Once you’ve cut your supports to your desired size, we recommend drilling them to the inside of the box in the middle of each section for extra stability.

Using your smaller pieces of wood, begin drilling these into the base on each side for extra support. Once in place, drill your base planks into these supports, making sure you’re leaving a gap between each plank to allow for drainage. Once you’re done, add a long supporting plank underneath the base for extra strength.

Install a layer of garden wire fencing across the base of your box before adding some landscape fabric on top, stapling both to the planks of wood. Always make sure that your landscape fabric goes up along the side of your box, as this helps prevent any damage or rotting. Once finished, add your compost and begin planting.

Decorative ideas for your planter box

Not sure how to style your wooden planter box? While planter boxes are versatile, choosing bright flowers to go inside can make it quite the garden piece. If you want a wild blooming box, go with an array of colours and species like cornflowers and cowslip plug plants, making sure that they can coexist beforehand. You can even create a planter box that has layers, elevating the space even more and adding that iconic modern touch.

Do it yourself planter boxes can be a fun craft project that brings a sense of natural elegance into your garden space. With the right tools and know-how, it’s a great springtime or summer job that any ability can enjoy.