As a school project, we had to design a module that combined urban gardening and events on the rooftop of Budafabriek, Kortrijk Belgium, which accommodates a FabLab (BudaLab) and different organisations, as well as event-space. It had to be easy-to-make, from readily available parts.

As a result, we came up with extruded equilateral triangles with a sac to hald earth & plants.
These modules are stackable, moveable, made from cheap timber, screws, PVC and elastic bands.
They can be used as planters, but also as bar tables and stools.

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If you have a pallet at home, the timber can easily be substituted for pallet wood (one side is 60cm, a europallet is 120*80cm).

WHAT DO YOU NEED FOR 1 MODULE?

MATERIAL
3 Wooden planks 18*93 mm
36 Screws
PVC pipe diam 32mm, 1m
Elastic bands
Varnish

WHAT DO YOU NEED FOR THE GARDENING BAG

MATERIAL
Thread
Anti-rooting textile

TOOLS
-Wood saw (hand, band or circular saw are all good)
Chisel or grater
Brush or paint roller
Sewing machine
Square
Tape measure
Drill incl. philipshead bit & drills (diam. 4mm (predrilling) and 10mm) (preferable cordless > screwing)
Pencil
Sanding paper (for example grades 120-220-600)

Check out this instructable for knowing how to make the gardening sack.
https://www.instructables.com/id/Triangular-planter-bag/

Step 1: Sawing & Drilling

Saw the wood to length and drill the holes.

Tips
Drill with a small drillbit first (for example 4mm), then from the front with a 10mm bit. This should fit 2 pieces of elastic band. Placing a leftover piece of wood underneath while drilling greatly reduces splintering at the end.

Step 2: Creating Hooking System

DO THIS IF YOU WANT TO USE THIS MODULE TO HANG A GARDENING SACK IN.
OTHERWISE SKIP THIS STEP.

The small planks need some more work done.
We make a hooking system for the gardening sack.

Step 1. Make two cuts with the saw.
Step 2. First work with the chisel for working away the big parts of wood
Step 3. For finishing use a rasp and/or sanding paper.

Step 3: Varnishing

If your planning on putting these outside, you'd best varnish the wood.

Varnish is always best applied in at least 2 layers, with sufficient time and a light sanding in between.
We sanded the corners before varnishing to better protect the corners of the wood. Follow the instructions on the label and/or ask in the store.Make sure the varnish is completely dried before continuing to work with the wood, in the meantime, let’s make a sack to garden in - inside the module!

https://www.instructables.com/id/Triangular-planter-bag/

Step 4: Making the Basic Panel

Screw the panel together according to following directions. One module requires 3 basic panels.

Step 5: Assamble Pannels

Step 6: Make a Nice Top Add-on!

Gardening in modules is cool, but modularity means they can have multiple functions!
So why don't we make a stack-on top to use the modules as outdoor furniture - even when there are plants in it?

To start, we draw and saw a 60° angle on a 39cm plank (fig1). We also saw 2 16cm planks.

The small planks can now be screwed onto the sides of the 60°point (fig2-4). To do this, first screw 2 screws halfway in on the small plank, about half a plankthickness from the sawn side, now clamp the pointed plank in a benchvise - with some leftover wood on the sides to prevent damage- and while holding the small plank at the end, screw the screws in completely.

The distance between the edges of the 16cm-planks should be about 1cm, so the top will fit on top of a finished module.
Make 3 of these supports, then saw out a large triangular piece of multiplex, sides of about 68cm. Fit the supports on it and screw them down (fig 5).

We finished by cutting away the sharp edge to a side of about 2cm.
You now have a top that makes a chair or table out of your (stack of) module(s)!

TIP: As before, it is best to varnish your wood after all sawing & drilling, but before joining multiple pieces together.