Preformed fibreglass ponds
The alternative to working with a flexible liner is using fibreglass preform ponds supplied in many shapes & sizes.
Check carefully before purchase for:
- Shelf variety and the proportion of deep water to shallow shelf area.
- Wildlife pond - Choose a shelf layout that has wider shelves for plants and shelves at different depths for variety of habitats for wildlife.
- Fish pond - Choose preform shape with more deep area and less planting shelf.
- Always measure your chosen space before going to the Garden Centre. It is easy to be misled by size when looking at an empty pond out of situ.
- Choose the largest pond your space will allow.
Fitting preform ponds into the ground:
- Often more tricky than you think.
- Mark out the profile of the pond and its shelves on the ground using a series of hose pipes or string.
- Measure the depth of each level.
- Dig a hole a little larger but as near as possible to the correct shape so that the preform sits snugly in the hole.
- Protect the preform pond from sharp stones with a layer of geotextile in the hole.
- Bed the pond into the hole so that it is level.
- Start to fill with water and place a spirit level over the top edge.
- As the water starts to weigh down the pond correct the level if necessary by backfilling the space around the preform shape with sand.
- Preform ponds have a horizontal rim around the top which is difficult to hide or camouflage into the garden.
- Water can only fill to just below that rounded top edge or the water will flow away.
- The only way to hide that rim is to securely fit slightly overhanging stones or coping slabs.
Preform ponds can also work well if placed inside a raised pond surround of concrete blocks. The horizontal rim can then be hidden under a securely fitted coping stone.