This brief article will teach you how to make solid, long-lasting planter boxes. Follow our step-by-step guide, and you’ll have great looking planter box in no time.
OVERVIEW OF PLANTER BOXES
The choice of materials that can withstand outside conditions is essential for all successful planter box designs. The ground, standing water, and a variety of wet soils and pebbles will undoubtedly come into touch with the boxes.
Galvanized or ceramic-coated fasteners should be used in all planter box installations. The timber should be treated with a GC (“Ground Contact”) grade if possible.
When performing outdoor projects, you need to be aware that some adhesives will not work well with treated wood. Liquid Nails is one of the few adhesives you can rely on time and time again.
Using a moisture barrier to protect the inside walls of your planter boxes is critical. External conditions can wreak havoc on the wood as it is, but your planter boxes’ inside will be constantly damp.
As a result, I use strong 6-mil plastic to encase all interiors. (I’ll discuss how to keep good drainage later.)
Here’s a step-by-step guide to building a planter box.
- MAKE A DECK PLATFORM
This is a terrific technique to raise the box to a more convenient working height, so you don’t have to bend over or go down on your knees to cultivate. You won’t have to fill your box with three feet of dirt, either!
I just cut 44 posts to a set height (about 14′′) to make these floor platforms. Then, using treated 24 pieces mitered at the corners, I built a rail system across their tops.
In most cases, laying the 2x4s down like this is not the strongest design. However, in this case, you can erect plywood walls afterward to give the box further strength.
I then build a platform by attaching pieces of 5/4 deck wood across the width of these frames. The deck planks are positioned with a lot of room between them (approximately 1′′). You can insert natural drainage channels at the bottom of the box by taking this approach.
Finally, use galvanized frame nails and brad nails to secure the pieces together.
- INSTALL PLYWOOD WALLS
To make sturdy barrier walls around the perimeters of the deck platforms, utilize treated 1/2′′ plywood panels. Make sure the walls are raised about ¾ of an inch from the concrete pad. The drainage area beneath the planter boxes can then be sprayed out with a hose on occasion.
Use a tape measure and pencil to note the proportions of the cuts for cutting plywood panels to size. Then snap lengthy “plotlines” between these measured markings with a chalk box.
Cut the plywood components to size, then shoot galvanized framing nails through the plywood walls to secure them to the deck platforms. After that, nail the horizontal 2x4s’ edges and the 4×4 legs together. This is how you can construct the planter boxes to keep the 2x4s from sagging under the weight of the plants over time. If you take this approach, you won’t need any additional large structural parts.
Plywood walls should be attached to all four sides of planter boxes. These ply panels do not need to be precisely connected to one another because they meet at the corners. Framing components on the interior and trim pieces on the exterior would provide further strength and concealment.
- ASSEMBLE THE UPPER FRAMING
Now you can erect an additional inner framework after estimating the measurements of the planter boxes.
Start by putting a 24 “rim” around the top edge of the plywood walls. Then use clamps to keep these pieces in place while you screw them into the plywood walls with 1-1/2′′ screws. You may also wish to join the long and short framing parts. Finally, insert 3′′ screws through their ends to secure the top frame.
Cut and construct L-shaped verticals to lay between the rim and the deck platform after the rim frame is in place. To trap things in place more effectively, bolt through the plywood walls into these vertical structural elements once again.
The boxes will be quite solid once this framework is in place!
4) USE HEAVY PLASTIC TO LINE THE PLANTER BOXES
Use the chance to line the interior of the planter boxes with strong 6-mil plastic before you start cutting. This can be accomplished by cutting two sections that would cover the floor and turn the walls 6 inches up. After that, cut long pieces to cover the walls and roll 6′′ onto the floor.
Staple the plastic in place using galvanized 1/4′′ staples. Then, in the crevices between deck boards, cut many tiny gashes into the bottom layers to allow moisture to “leak.”
To establish an appropriate drain field below the soil, fill the bottom 5′′ of planter boxes with washed stone.
6) ATTACH THE VERTICAL TRIM
Trimming these boxes may be done in a number of different ways. Horizontal decking, galvanized metal, and even cedar are all attractive options.
Simply glue treated trim pieces to the exterior walls of the boxes, butting them together side-to-side, to establish this trim profile.
Position the trim pieces 3/4′′ off the ground, just like the plywood walls, and use glue to adhere them to the backs of the pieces. Then, further secure them using 1-3/16′′ galvanized brad nails, which are just long enough to punch through the inner wall but not quite long enough to punch through the outer wall.
7) ASSEMBLE THE TOP RAILS
Pull down a 5/4 deck board to make it just broad enough to cover the timber beneath it and have a 1′′ overhang on the outside, for a total of around 5′′. You can then cut the pieces with mitered corners and hold them in place with glue and brads, much like the trim boards.
Sand the rim of the new cap, as this is the most likely region to come into contact with skin and clothes.
After putting the planter boxes together, let the adhesive set for a day before moving them to their final places. Protect your carpentry business with insurance for carpenters.