How to make an alpine trough

Step 1

Mix together two parts sieved coir fibre, one part cement and one part sharp sand. Pour water into a well in the centre and mix it together to form a stiff paste.

Step 2

Using a trowel, place a 2.5cm layer of concrete into the bottom of the larger cardboard box. Ensure the concrete is spread into the corners.

Step 3

Cut a piece of small-gauge wire mesh to fit the bottom of the box. Place it on top of the mixture to reinforce the trough, and add a further 2.5cm layer of cement over the top of the mesh.

Step 4

Push 5cm-long pieces of wooden dowel into the base of the trough for drainage. Then, place the smaller box inside the larger one, leaving a gap of around 5cm. Add bricks to weigh it down.

Step 5

Insert sections of mesh along each side, cutting them shorter than the depth of the box so they'll be hidden.

Step 6

Add cement to the sides of the mould to make a wall. Use a stick to push it into the corners. This will prevent air pockets from weakening the walls.

Step 7

When all the concrete mixture is in place, support the outer sides of the box with more bricks. Then cover the entire thing with a plastic sheet.

Step 8

After two days, when the concrete is set, remove the sheet of plastic and supporting bricks and peel the cardboard away from the sides.

Step 9

The sides of the trough can be aged by roughly scraping them with a trowel. After a week, use a hammer and large nail to push the wooden dowels out of the trough, leaving holes for drainage.