This advice is intended for anyone installing a small (under 1000 gallons – about the size of 10-person hot tub or less) prefab garden pond or other little container pond on a patio or balcony.
I’ve had several different types of ponds over the years, and, after a few learning curves, I’ve got a system I really like—easy to care for with healthy water, plants, and fish.
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Clean and Natural Pond Care
I not only garden organically but I keep my ponds the same way. I do not use any chemicals, I let nature do its stuff (because what, I ask, is more wonderful than that?), and I am thrifty, making use of used materials wherever possible. Having a pond does not have to be a huge chore or expense.
Here’s a pond I saw on a garden tour. This was what inspired me to have my own:
The goal is a low-maintenance, healthy, good-looking pond with clear water and happy fish.
I highly recommend a smaller pond because it’s easy to manage, fits in small spaces, and the pump will use a minimal amount of electricity.
If you get enough sun, you could also use a solar-powered pump.
Steps for Building a New Garden Pond
Each of these points are explained in detail below.
Quick Links – Starting a New Pond
4. Dig or Build
5. Add Water
Put safety first. If there are young children around, ponds are not worth the risk. It’s a lovely addition to a garden but only if you are certain it’s safe.
Check local bylaws to make sure you are indeed allowed to have a pond. Make nice with your neighbors so they don’t try and throw a wrench in your plans.
What you will need A suitable location, away from trees, so you won’t be disturbing tree roots when you dig, and won’t have lots of leaves falling into it in the Fall. You will also need year-round access to an outdoor GFCI (Ground Fault Circuit Interrupter) electrical outlet for the pump.
Every single summer I see a few prefab pond forms out at the curbside, free for the taking. Before you try and buy one new, check Craigslist, FreeCycle (and equivalents), and Kijiji online. See if there are any ponds and pumps advertised and also place your own want ads. Reuse benefits us all and prevents perfectly good stuff from going to landfills.
I also see a lot of abandoned ponds when viewing houses for sale. It never hurts to ask if the homeowner would like it removed free of cost.
If you don’t have any luck, and you like your money, at least wait until end of season sales so you can pay half price.
Put your pond where you can enjoy it. I’ve been on so many garden tours where the gardener reveals that they put the pond way at the back of the yard thinking it would be too noisy near the patio, and as a result they never get to spend time near it.
First of all, they’re really not noisy but also, you can turn the circulating pump off at any time. Isolated ponds are also prime fishing areas for raccoons. Be realistic. If you like to sit and read outside, have your little pond nearby.
And if I haven’t convinced you already, consider the fact that your pond will require year-round care. Here, that means ensuring the pump is functioning fine in the coldest, snowiest days of winter. Am I happy my pond is now right near my front door? Yes, I am.
Pond forms can go into the ground, using the actual pond form itself to guide your digging, or you can place on in a raised bed like I did. I really enjoy having the pond raised up a bit. It’s easier to maintain and it seems safer in our open yard. No one is going to accidentally step into it when there is snow cover.
No matter what, make sure you end up with the pond firmly in place with soil firmly packed all around the outer sides and bottom, leaving the pond plum, and level before you add water. It’s worth the work to ensure the placement is perfect because otherwise, when you’ve got it all ready, the un-level water will drive you nuts, look wrong, and possibly overflow out the lower side when it rains.
Start with a perfectly clean pond, removing any dirt before adding water. If you’re using tap water, it will have chlorine in it. Once full, leave the pond alone for 2 full days so the chlorine can off-gas. Your future plants and fish will be off to a better start this way.
You can get the pump and filter (it’s called this but it’s really one unit) going while you’re waiting for the water to off-gas the chlorine. You can add plants when the water is ready (2-3 days). Fish come in 2-3 weeks when the pond has started to come alive with scum for the fish to eat.
Recirculating pumps are made for various size ponds. If you don’t know the water capacity of your pond, there are charts online to figure it out based on a few measurements. A 450-gallon pond uses a 450-gallon pump. Simple as that. As long as your numbers are a close match (or the pump is a bit stronger), you’re fine. A higher power pump would move the water too fast and hard, making it murky and loud. A lower power pump would not provide enough water circulation to keep the water sparkling clean.
The way these pumps work is, they draw in the water at an intake point and expel it through an output. I put a short hose (with a hose clamp) on my output valve so I can direct the water how I want it. You can create a waterfall, spray feature, or simply send the water back into the pond. The farther you are sending the water through a hose, the more pump power required. You can get specific advice online or in a garden shop that sells pond equipment to know what strength pump you need.
My pump sits on a ledge in the pond about a foot below the surface but it’s also fine to rest it on the bottom or on top of something in the pond. I cut the output hose so it is just above the surface of the water. It provides a gentle trickling sound but doesn’t waste any water. If you have sprays or waterfalls, you will lose water to the wind. The fun part is that fish love massages and will play in moving water for hours, riding the current and then jumping back in for more. It’s very sweet.
TIP: Buy two pumps so that if one malfunctions, you can immediately use the second one. You will thank me if your pump fails in the cold of winter and your fish risk freezing up.
Energy saving tip: put the pump on a timer and run it just as much as you need to keep the water clear. Be willing to experiment and find what works for you.
Now the filter trick
Initially I was told I must have an expensive biofilter to have a healthy pond. After fainting at the prices, I made my own. And it worked fine. I also made one for my mother’s pond and it’s still working fine four years later.
But then, I thought about it some more. What is the biofilter doing? It’s just grabbing crud from the water as it is sucked toward the recirculating pump. For the most part, it’s beneficial crud, but if you can keep it from the water at large, you will have clear water. Ponds become an elaborate and wonderful ecosystem all their own and you will not have a thriving, healthy pond if you impose human “clean” standards on it. I realized there was an easier way.
TIP: If your fountain spray or water flow is really vigorous, the water can’t become clear because, quite simply, too much gunk is being thrown around in the current. Play with the pump flow levels to find a happy medium. Allow a few hours for each test.
Add plants. Wait two to three weeks before adding fish.
I have around five pond plants at any given time. Like any gardening, you have to willing to try things out and let nature tell you what will work. Some water plants grow crazy root systems, others spread too fast, and so on. The goal is to have healthy, good-looking plants that fill the space without overcrowding it, and provide shelter and nutrients for the fish.
Water plants are generally potted in plastic or wire mesh baskets with specific water plant potting soil and some small rocks or stones to keep the soil in place.
I have found it takes about two or three weeks after plants are introduced to have an environment that is ready for fish. If you bring the fish in earlier, there’s no scum on the side of the pond for them to eat.
TIP: Position your water plants so that the lip of their containers is just a tiny amount above the water surface or slightly submerged. This way birds can stand there to bathe and any little swimming critters like frogs or mice have a way to get to land.
There are a lot of plants that are toxic to fish and can really murk up your water, so you have to think before you plant around your pond. Fallen leaves can poison your water. Here’s one list. You can Google for more information. I honestly never thought of this when I first set up my box pond. I had to remove a bunch of plants from around it last year when I realized they probably killed some fish and made the water look gross.
If you want to know which aquatic plants I am growing in my ponds, you can see them here.
The video (above) shares how to introduce fish to your pond.
If you want more information on preparing the pond, to be sure your fish will be healthy and happy, this post has good information, including how to calculate the right number of fish for the space available.
Check the pump regularly for any build up of gunk at the intake area. Never put your hands in the pond while the pump is on. There’s a risk of electrical shock.
I just leave my quilt batting filter in place year round. It will turn green and fill with gunk, just as you want it to. Every year or two I change the batting if the water isn’t staying clear.
Some water will evaporate year round. On really hot days, my pond can lose as much as six inches to evaporation. I’m lucky because we get a good balance of rain and that tops it up. If you must add tap water, place it in open containers first to let the chlorine off-gas. Wait 2-3 days and then add it to the pond.
If you go on holiday, arrange for someone to check your pump once a day to make sure it’s running. I’ve known a few instances where wild animals displaced the pumps and the output hose ended up spewing all the pond water out of the pond, leaving the fish in just an inch or two of water. Not good.
You have to keep the water circulating through the winter months so the fish and plants don’t freeze in ice. Read more here…
~Melissa the Empress of Dirt ♛