Our "DIY" Koi Backyard Pond!



For years, I've always wanted a pond ecosystem in my backyard. Over the course of several trips to Japan, I had become fascinated by koi ponds. However, due to budget limitations and safety concerns (we didn't want our young daughter to risk falling into a body of water), we've always put our pond project on the back burner - even selling the prefabricated pond basins we once had acquired during a garage sale years ago.


But with the pandemic, and with ample time on our hands, we decided to do some research... And quickly realized that a pond may no longer be out of our reach. I initially only wanted a simple "hole in the ground", with a few rocks and pebbles, a little stream of water, and a few sturdy gold fish. But after talking about it, and looking at several pond photos on Pinterest and other sites online, we decided that building a pond inside a garden box would be a better looking, and a longer-term option.


We have a BIG yard, which is awesome when we have dogs over, but which is strangely inadequate for complex landscaping projects due to its exposure to high winds and blazing prairie sun. One of the pros of building the pond in a garden box is that if we were ever to be "done" with the pond, we could always convert it into an actual garden box. As we also needed proximity to an electricity outlet (for the filtration pump), we decided to build the box along our eastern fence, near our existing garden box and closer to the house, so we could enjoy the sound of the stream and even see the fish from our dining room window and our deck.


Note: This is not a monetized blog article and we do not earn a commission from the links provided. What worked for us may not work for every project.


The location of our future pond, by the fence between two lilac plants.
The location of our future pond!

After determining where we would build the pond, the next step was to remove the sod and dig a hole for the deepest part of the pond. This was probably the most physically challenging part of building the pond, as the ground was very hard and full of clay and rocks.


Our old kiddy pool was put in place at the very bottom of the pond, to protect the bottom of the pond liner from being punctured by the ground, and to give the pond a nice, rounded shape.


The perimeter of the future pond.
First, we removed the sod and dug a hole where the pond would be.

The following step was to build the actual box. We purchased some treated lumber and wood stakes from our local Home Depot (which was pricier than expected...) and put the box together within a few hours.

Preparing the pieces of wood required to build the box.
Putting everything together and making sure it's levelled.

The next step was to purchase some soil to fill the box. We ended up getting a cubic yard of screened loam from a garden supply shop, which would fill the majority of the pond box, and shape a shallow area of the pond plus an elevated spillway/creek. Several bags of dedicated garden soil would form the top layer for planting.


We then proceeded with putting down the pond liner and filling the hole created with water. Once that looked stable enough, we worked the perimeter with a wide variety of small, medium and larger rocks to give it a natural look.


Filling the pond with water! No leaks!
Working the perimeter with rocks and pebbles of different sizes to give it a 'natural' appearance.
Creating the spillway/stream.

The next step was to install the filtration system. As we were on a budget, we built a DIY filtration box composed of a submersible water pump placed inside a small plastic box (purchased from Dollarama) filled with filtration material and bio balls. The pump was then connected to a partially-buried 5/8" tube, sending the filtered water up to the spillway.


Our DIY filtration box.

After finishing the final touches to the rocks and the position of the filtration box, we then proceeded with filling up the box with additional soil and adding vegetation.


While at the garden center, we selected hardy and aromatic herbs (rosemary, lavender and mint), as well as a blueberry bush, "hens and chicks" and a small Alberta Dwarf Spruce. For pond plants, we picked a basket of "purple pickerel weed" and a "water hyacinth". A nice neighbor also gave us some tiger lily bulbs for some added color.

A Japanese lantern, a Fairy Garden and a Toad House were the final touches to the pond landscape.


At this point, we are still undecided if we will add some ground cover, like mulch or additional rocks and vegetation.

The current look of our pond!
Mint and the Toad House, 'coz you never know who may be coming for tea!
The pond wouldn't be complete without a Japanese rock garden.
We hope the water hyacinth and the pickerel will bloom this summer!

As we are still in May, our pond will be very much a work-in-progress for the season! But we already enjoy this added feature in our yard and the sound of the water coming down the stream. :)



The challenges ahead for our DIY backyard pond will be to:

- Keep the water ammonia levels low

- Keep algae under control

- Ensure our future fish (hopefully koi!) stay healthy and happy

- Protect the fish from potential predators

- Make the pond as bird and bee friendly as possible



Do you have a backyard pond? What were the challenges you faced? We'd be very interested to know your experience! Tell us on our Facebook page!


To be continued....