³ÉÈË¿ìÊÖ

Instructions:

• We used the offcut of a plastic civil engineering pipe which was going to be thrown away. But you could use any watertight container or preformed pond.

• To protect the liner from being punctured by stones, we cut up some old dumpy bags and laid these over the base, followed by a shallow layer of builder's sand. As an extra precaution, we also lined the whole of the inside with a felted pond underlay. This was especially important for the top edge of the pipe as this was quite sharp.

• We used a butyl rubber liner which, although expensive, will last a lot longer than polythene or PVC. When buying a liner, always buy more than you need. Your pond liner supplier will be able to advise you, and many now have an online calculator to help you.

  All you need is the maximum length, width and depth of your pond. But as a general rule, the liner should measure the maximum width of your pond plus twice its depth, by the maximum length plus twice its depth. On top of this, you’ll need to add at least 15cm (6in) on both the width and length measurements to allow for an overlap at the edge.

• It’s best to get someone to help you put the pond liner in place. It can be awkward job. And remember to fold in the pleats along the side before filling the pond. There’s no going back once the water is in! Once full, trim the liner to size. We left an overlap of 15-20cm (6-8in) to disguise the edge.

• To build a stone wall around the edge, you need to first lay a foundation. We used a 5:1 ballast cement mix. This foundation should be at least 200mm wider than the width of the wall and 150mm deep. We used Welsh dressed slate for our wall. Try your local garden centre, builders merchant or local quarry to see what is available in your area.

• Our slate was spilt into thin pieces and stacked together in layers one on top of the other. It was a bit like doing a jigsaw as every piece was a different size.

• Topsoil was added to fill in the gaps between each piece of slate. As the wall got higher, we then began to slot in our alpines. It’s crucial that you do this as you go along, as it is very difficult to do this afterwards. It also helps to buy plants in small pots. Anything larger than 9cm (3in) would be difficult to cram in.

• We used a range of white-flowered alpines to tie in with the white and silver scheme of our Twilight Garden. But you could use any alpine or hardy succulent. Houseleeks are particularly useful as they can withstand being baked on a hot, sunny wall. Saxifrages and lewisias prefer cooler conditions and so would suit a more shaded position.

• The gap between the pond and the wall was backfilled with topsoil as the wall went up. We used a piece of wood to pack it down after each filling. The alpines and succulents should grow into this.

• As we got near the top, we wound round an old bit of garden hose. It already had a few holes in it, but we made a few extra with a pair of secateurs. Shop-bought seephose would be a suitable alternative.

• One end of the hose was bent back on itself and tied up, while the other was left jutting into the wall. By attaching a hosepipe to the latter, the plan is to keep the topsoil behind the wall topped up with water at regular intervals.

• Once the topsoil has completely settled, which may take a several days, the precut capping stones will need to be cemented in place. Ours have been precut to 350mm so that they will be stand flush with the outer face of the wall and hang over the inside by 50mm. The cement will take about a week to dry.