(Editor's Note: This article was originally published on November 3, 2007.)
X Marks the Spot
Picking an appropriate spot for your pond is key. Full sun is best for plants and fish. At least 6-8 hours of full sun is recommended to promote healthy plant growth, beneficial bacteria growth, and to keep your pond somewhat defrosted in harsh winters. Steer clear of large trees to avoid large roots and falling debris in your pond. It can also be hard to incorporate a pond into landscaping to make it look like it belongs. I found it very helpful to make several drawings of different layout designs for my landscaping before I ever started digging.
Since I was not using a rigid pre-formed pond liner, I got to decide the shape of my pond. The price difference between a pre-formed liner and a black plastic liner is not overly considerable, so you can pick which way you want to go. A pre-formed pond can run $100-$150, while a plastic liner can run from $40-$80 depending on size. My thought is that digging a hole to fit something else is WAY harder than putting a liner over a pre-dug hole.
Pond guides often say that you should use a hose or thick string to lay out the shape of your pond. This is one of the steps I skipped as I had been imagining this pond for quite a while at this point, though it wouldn’t be hard to do this step if you need to work it out visually before you start digging. Another way you can accomplish this is by chopping a vague outline with your shovel before you start, which can be altered as you go.
Dig a Hole
Digging your pond hole will probably be the cheapest, but longest and hardest part of your do-it-yourself pond. I could mention renting a backhoe, but since this is a thrifty pond, I suggest two people with two big shovels.
Not only is it the cheapest section of the program, but it is the most crucial that you do it right. Most guides will tell you to start in the middle and dig out to the edges, but I don’t think it matters so long as the hole gets dug. While digging your hole, the deepest point needs to be at least 18 to 24 inches and can reach up to 3 to 4 feet deep, which you can measure by laying a 2x4-inch board across the pond and using another 2x4-inch board as a marker to measure.
Your pond needs to have shelves around almost every edge of the pond for bog plants. The shelves have to be level and should measure 6 to 8 inches wide by 6 to 8 inches deep, which will be easier to set gallon pots on without struggling to keep them upright in water. My shelves aren’t level and are only on 2 ends of the pond, which I regret.
If you have not started on level ground, make SURE the edges of the pond are level by laying a 2x4-inch board across the edges and checking with a level. This is crucial! I didn’t do this and now my pond is full on one side with the liner exposed on the other. I am still trying to fix this retroactively.
While digging, I also recommend putting a level, deep spot for your filter. Mine is on an unleveled spot and now all my fish hide underneath it and I hardly ever see them.
One other step you cannot skip is making the edges slope away from the pond. This will help keep any runoff from the elements from going into your pond as well as making a more stable base for your surrounding stones.
Once the hole is deep enough, level, and the shape suits your fancy, then you can lay the liner in it. Most pond building guides suggest you add 2 inches of sand to pad the bottom of your pond so your liner won’t rip. The way I see it is, why would I dig a 2-foot hole only to start filling it up with sand. So I skipped this part and I have yet to see a problem because of it. Thicker 20mm liner will not rip because of a little stone or root.
Plastic pond liners come in an assortment of sizes, so measure your pond before going to the store or ordering online. Don’t forget to take into account the depth along with the width and length, which will add some extra needed liner.
One trick I accidentally learned is that if you buy a liner that is too small, and/or the next step up in liner is way too large and expensive, there is such a thing as pond liner tape to splice two pieces together.
Duct tape should not be substituted. In my case, my liner was far too short, so I cut the excess from one side of my pond and used the $12 liner tape to make the liner big enough.
Tack the edges of your liner down with a few temporary bricks or stones.
Try to get most of the wrinkles out, is what most guides say. What they don’t say is that this is very difficult. Just do your best. Once plants, river rocks, fish and algae are introduced you won’t see most of the wrinkles anyway.
At this point you need to trim the excess edges of the liner to the contours of the pond edge. Pond guides will tell you that you need 10” of extra liner around the whole edge of the pond. I have yet to see any problems in the few places where mine fell short of that. I suggest keeping as close to it as possible though, to avoid leaks and collateral spray from any fountain you may put in.
In the next article in the series, I will discuss adding water, attaining healthy water quality, and adding life to your pond. Hopefully this issue will keep you busy until then. Remember to keep your final product in mind when you start to grow weary!