The Half-Acre Habitat

The Wildlife Pond

So, I’ve talked around it, and even talked about building it, but not specifically about the reasoning behind it – we now have a wildlife pond in our backyard.

I grew up in a place where ponds were large – a ¼ acre or more – and muddy and where one fished for catfish and where the cows drank. This is not that sort of pond.

Neither is it a koi pond, where exotic goldfish swim.

It is a pond designed for frogs. And dragonflies. And birds. It is, when all is said and done, a wildlife pond. No other project I have done has elicited so many comments and questions, so I will attempt to answer some of them here.

Why did I build a wildlife pond?

Amphibians are in trouble. Their habitat is in decline, and their populations are plummeting. So I decided to make them some habitat to go along with the habitat I am already building for birds. And speaking of birds – they are more drawn to water than they are to feeders, so that is a bonus. And since I’m building a habitat for all the animals that live on my property, of which I am one, the fact that I love moving water is not incidental to the decision.

There are a lot of resources out there if you want to build a fish pond in your backyard. There are a lot of resources if you want to build a fountain. But as I researched wildlife ponds, nearly every single thing I could find supposed you lived in the UK. Apparently, wildlife ponds are a big thing there. So I had to do a lot of translating as to climate and so on. This post is my attempt to explain how I did it, and my reasoning behind some of the decisions I made.

It’s six feet wide and ten feet long and is 4 inches deep at its shallowest point and 18 inches deep at its deepest. Much like a swimming pool, there is a shallow end and a deep end. Your pond needs to be deep enough so that in hot climates (like mine) the water will stay cool in the deep parts. If you had fish, it would need to be deeper, but I don’t have fish, nor do I plan to add them. But more on that later.

The shallow end is for birds – it slopes from zero to 4 inches deep, with rocks here and there in the shallow end for the birds to light on. The robins, doves, and finches use it daily for bathing. The slope is also important for frogs and other critters to get in and out of the water – like a beach of sorts. Almost all the frog spawn we get is in the shallow end.

I dug the whole pond in an afternoon after it had rained and the ground was soft. We have clay here, so it was a pain, but the hole held its shape. I don’t know how one manages in sandy soil. It’s important that the perimeter of the hole be level – this meant I took some of the soil I dug up and used it to build a berm on the low side.

After digging the hole and tamping it firm with a tamper, I put down pond liner underlayment and then a 45 mil EPDM liner. This was by far the most expensive part of the build. There are cheaper liners than EPDM, but it is the one that professionals use and is reliable and durable. It has a 50-year life expectancy, which is 20 years longer than mine at current rates, so we should be good.

Some places will tell you to use old carpet or sand as underlayment, but underlayment is cheap, and this is part you don’t want to get wrong. The underlayment protects the liner, and I don’t want to deal with punctures.

After the liner is in – a pain, and you can probably use another person’s help here – you just add water, and then the weight of the water will press the liner into the creases of the hole. You will want to get in the hole as it fills, so you can shift things around as it fills. What sort of water you use is a matter of choice – I used tap water from the hose, but if you do this, know you need to let it sit a few days to let the chlorine dissipate before you add plants or anything. Some people just let the rainwater fill the pond, which is probably best, but I would still fill it the first time with tap water to set the liner. You could then siphon the water out and let it fill with rainwater if that is important to you.

At this point, you want to take a break anyway. Let the chlorine dissipate, and let the liner get settled. You can use this time to order your plants and find a source for rocks.

When we lived in North Carolina, rocks were everywhere – for free. I planted an apple tree once and unearthed five or six bowling-ball-sized rocks in the process. But this land was once prairie, and any rocks here were transported here. So, I went to the expensive landscape rock place and looked at rocks that cost $700 a ton. Then I went to the place that sells gravel and bought limestone rip-rap for $45 a ton instead. I ended up using a ton and a half of limestone rocks, ranging in size from roughly an apple to two or three the size of a duffle bag.

There are lots of ways to edge a pond, but I like rocks, and since this was close to the house, I liked that rocks were clean and easy to do and that they would create hiding places for amphibians and the green anole lizards we have everywhere here.

Placing the rocks is more art than science: Trim the liner to about six inches beyond the hole’s edge, then place rocks around the inside of the hole against the walls, as if you are lining the hole with rocks. This creates pockets where tadpoles will hide. Then place rocks around the perimeter to mark the transition and to hold the liner in place. Big rocks first, then smaller ones, then finally get some bags of gravel to fill in the remaining spaces. My liner is invisible because it’s completely covered with rocks. This keeps the liner from getting UV damaged, keeps the pond cooler, and also looks much more natural.

Everyone asks about mosquitos since we don’t have fish, and we use a 3-part strategy to prevent them: We have moving water, we plant for dragonflies, and as a failsafe, we use mosquito dunks. Mosquitos need still water, so we bought a simple pump and spitter that turns all the water in the pond over once per hour. This also makes for lovely sounds and is visually interesting.

Dragonflies showed up on the second day, and have been here ever since. They eat tons of mosquitos. And dunks are floating cakes made of bacteria that kill mosquito larvae and nothing else – we replace them monthly and they cost pennies.

We don’t have fish because they eat amphibian eggs and they poop – a lot. The nitrogen in the poop causes all sorts of filtration problems. People who have koi ponds spend thousands of dollars and lots of time filtering the poop out of their ponds. And koi are not endangered, but frogs are. So no fish.

A wildlife pond needs plants – preferably native ones. You want 60% of the surface of the pond to be covered with plants. This is a goal – right now I have swampwort and watercress and rush and papyrus and Louisiana Iris and water lilies growing in the pond, and canna and daylilies growing on the edges. I have ordered some more plants – If there is a downside, it is that pond plants are hard to find in most nurseries. Had I planned ahead, I could have had the plants lined up in advance.

The plants provide shade, habitat for the wildlife, food for the wildlife, and also make it look nice, which is also important to me. A pond is a whole new ecosystem, and it all plays a role.

I built a small landing pad patio beside the pond, so I can sit next to it in the afternoon and watch the birds bathe and hear the soothing sounds of the water. At night, the frogs sing, and I have hundreds of tadpoles zipping about in the water. Lizards sun themselves on the rocks, and in the morning, I walk the edges, looking for frog eggs that were laid overnight. And watching the birds bathe is pure joy.

It’s my favorite addition to my garden, and I wish I had done it years ago. The total cost was around $800, and it took a month of nights and weekends to do, but I probably could have done the whole thing in 3 days with planning.

If you have any questions, put them in the comments and I will try to answer them.

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