My Unexpected Frog Pond

I never dreamed of making a frog pond, so mine isn't the result of planning and implementation. Mine is the result of responding to what nature was doing. I started this tread as a place to keep a record of this amazing adventure.

Background

When we bought our place in 2009, our next door neighbor told us it used to have an inground swimming pool. He remembered swimming in it as a kid in the 1960s. After I cleared out several years' worth of overgrown brush, we found it, long since filled in.

March 2010.

We've occasionally pondered what we could do with it because it seemed like we had a ready-made foundation for something. The top two options were a cistern for rainwater or a root cellar. To properly assess our options, however, we needed to dig it out to see what's what. About a year ago, Dan rented a excavator and did just that.

November 2019.

Final digging out was finished by hand.

It measures 11 by 24 feet, 3 foot at the shallow end, 6 foot at the deep end. What could we do with that?
One detriment to the idea of an underground cistern, is that it has a big crack.

Vertical crack from top to bottom.

Close-up

The crack meant more discussion. In the meantime, it started to rain.

November 2019

By early summer, it was consistently holding quite a bit of water.

June 2020

This is when I discovered...

TADPOLES!

All other plans got set aside and we hoped our little frogs would make it. The water level fluctuated a lot between heavy rains, leakage through the crack, and long hot dry spells. The amazing thing was that the water never stank, nor did it create a large mosquito breeding area. I felt like we ought to do something, but I wasn't sure what.

A Plan to Accommodate

A couple months ago, I discovered the frog habitat badge bit for the animal care PEP badge. By this time, our pond looked like this...

November 2020

I read all the articles and watched all the videos. I also checked out pond books from the library. I needed mud and plants. We had some mud...

The bottom of the pool was covered with a mix of leaves and mud.

But I needed lots of plants. But because the water level fluctuates so much in our pool, I decided to start with floating oxygenaters.

Hornwort, an oxygenator, purchased from a local aquarium store.

I was concerned the water might be too acidic for it, so I did a simple pH test first.

I was surprised that the water sample looked relatively clear

I was even more surprised that the water pH was so close to neutral.

After I introduced the hornwort, my next step was to build a chinampa.

I used cinder blocks for my chinampa.

First course completed.

Ready for planting.

Planting will have to wait until spring, because I'm not finding many pond plants available in December. I did find duckweed, however. It helps suppress algae growth and acts as a natural biofilter of pond water.

I found duckweed for sale on Amazon.

My duckweed corral.

The duckweed corral is made from an old plastic crate kept afloat by tying pieces of garden timbers to it. This was originally an experiment, trying to figure out if I could float potted pond plants in it. That didn't work; soil-filled pots sank.

But the frogs found a use for it.

Because of the changes in water level, I'll probably stick with submerged and floating plants for the pond itself, and marginals that don't mind occasional dry conditions for the chinampa. I'd like to plant cascading plants around the concrete edge of the pool to make it prettier.

Water level after a heavy rain.

Current Status

Typical winter water level.

What's especially exciting about the above photo, is something that just started happening a couple of weeks ago - the water is clearing!!!

A view of the leafy pool bottom framed by reflections of tree limbs and laundry.

This discovery was so exciting! I almost couldn't believe it. We must be doing something right! Very encouraging, and very fun that this was so unplanned and unexpected. I'm looking forward to doing some planting this spring.

To be continued . . . . . . . .

So neat!
Consider parging the inside of the pool surface bonding cement.
Its said to be good waterproofing.

Are you directing water from your roof into the pond?

Thanks, William! We've discussed somehow patching the crack, but at this point don't want to drain the pool down to the bottom of the crack. That may be possible later this summer when the water level lowers.

All* our rainwater gets collected for garden and plant irrigation and livestock water. What we are planning to do, is to make a greywater filtration bed to empty into the pool; our phase 2. It will to keep the water level up when we hit our annual summer dry spell, plus I'll be able to grow more useful pond plants. :)

*EDIT: Technically, not all. Just as much as we've got collection tanks for.

What about building something like another chinampa, only taller, with the tallest part pressed against the crack? It might not stop the drainage, but it would slow it way down.

I fixed the concrete birdbath a couple years ago with the black flex seal paint and it has held up quite well.  Not to sure how permie “flex seal” is but worked.  I built a Bill Mollison herb garden (from his permaculture book) for my mom probably 30 years ago with the small pond at the bottom of the spiral but I never could get it to hold water. Too bad they didn’t have flex seal back then.

Wow, what a sweet thing to find in your yard. Have you thought about turning it back into a swimming pool? Research "natural swimming pools" to see some ideas, here's a photo of one I just picked at random swimming pool.

You can have your plants, your frogs and fish! Plus play in it when it's hot. I have something similar but much smaller, all we can do is stick our feet in to cool off. Only drawbacks is you need a pump to circulate the water through the planted filter areas and you might need to put a liner in it. Although I suspect if the plant areas was large enough you might not need the pump. Any problem with mosquitoes even if your climate gets cold could be mitigated with mosquito fish, Japanese Rice fish or White Cloud Minnows. Might be other small fish native to your area that you could find. If your weather is a little warmer lots of so called tropical fish would also be happy because many of them aren't really tropical at all. Heck in a pool that size you might even raise something like bluegills and eat them.

Don't mean to tell you what to do, I just love to have something like that myself so I'm just a little bit jealous.

Ellendra Nauriel wrote:What about building something like another chinampa, only taller, with the tallest part pressed against the crack? It might not stop the drainage, but it would slow it way down.

Ellendra, hmm. That's definitely an idea to explore, thanks!

Rob Griffin wrote:Not to sure how permie “flex seal” is but worked.  I built a Bill Mollison herb garden (from his permaculture book) for my mom probably 30 years ago with the small pond at the bottom of the spiral but I never could get it to hold water.

Rob, it doesn't sound very permie, does it? I believe there are threads about sealing ponds here in the forums, but I'm guessing it would be for dug, mud bottom ponds. I do know pigs can be used to seal mud, but I don't know exactly how.

Mark Reed wrote:Wow, what a sweet thing to find in your yard. Have you thought about turning it back into a swimming pool? Research "natural swimming pools" to see some ideas, here's a photo of one I just picked at random swimming pool.

Mark, that pool is very cool! The last chapter of Building a Better World in Your Backyard is about natural swimming pools. I need to re-read it with a view to what we're doing. It's really nice to have a hardscape feature like this and turn it into something functionally permie!

The former owners of our property put in a small ornamental pond in a rocky area behind our house. I was quite surprised when I just left it alone, how the Lemna duckweed showed up and tadpoles from our native tree frogs soon followed. Despite no pump to aerate it, the water stays quite clear which I think is thanks to the Lemna. In the summer it covers the whole surface which helps reduce evaporation, (but we still have to add water most summers). Tree frogs are adorable and I've found them 7 ft off the ground on my Scarlet Runner Beans, among other surprising spots. Considering the pressure our amphibians are under, giving the pond to them is fine by me.

When the Lemna gets to thick, I feed it to our ducks. Their response is, "what - that's all? More, more, more!"

I've heard fish and tadpoles don't coexist well in small ponds,evidently the fish eat the frog eggs.
My own "pond" is a mere 55 gallons and not even full yet.
I want frogs over fish, though I'm told Southern  Ohio is more toad friendly than anything.

I love the idea of feeding your pond with greywater, nice function stacking there.
Duck weed is awesome, Azolla maybe even better, since it fixes its own nitrogen.
Both are said to make great feed and fertilizer.

Jay, that's good to hear about duckweed helping reduce evaporation. This spring we plan to get Muscovies again, so I know I won't have to worry about an overabundance! I read it's great for the compost and makes good mulch too.

William, when I originally thought about a pond, I thought fish too, but nature made the decision for us. I read that about fish eating frog eggs, so if we ever do want fish, we'll have to make a separate pond. Interesting about the azolla. I didn't realize it was a nitrogen fixer (a huge plus). I went with the duckweed because, as I mentioned to Jay, we plan to get Muscovies again this spring. So the duckweed will be feed as well. It's very interesting to compare ideas and notes. I'm learning a lot!

I have bluegills in my pond and an old gold fish/koi cross named Gladys. They all live happily with lots of frogs. The frogs just moved in on their own but they don't breed in there. Toads on the other hand arrive each spring and breed like crazy. I don't know if the fish eat any of the tadpoles or not there are so many of them I can't really tell. Later, little tiny toads are hopping all over the place. Of course there are lots of plants, waterlilies and hornwort mostly, so plenty of places for small things to hide. I'd like to get rice fish or white mountain minnows but I'm sure the bluegills would eat them.

Well, when you said unexpected, I was expecting the giant puddle I found this year with hundreds (thousands?) of tadpoles. We certainly didn't have issues with mosquitoes this year. This is way cooler, though.

A chinampa is on my list for our pond, but it's a long ways down. Did you do something to reinforce the cinder blocks? Maybe the force of the water pushing in will hold then I'm place, but I'd be paranoid about part of the wall collapsing and losing all of my soil into the pond.

Either way, cool to see your setup, and cool to see how much the water has cleaned up.

As far as patching the pond... do you really need to? Especially if you're adding gray water? If the pond is completely impervious, then it won't do much to hydrate the surrounding landscape (without actively removing water with pumps or buckets of whatever.) Personally, I'd want to slow water down, but not stop it completely (unless it were being stored for drinking.)

On the subject of azolla, does anyone have a source for the temperate species that Carol Deppe mentions in The Resilient Gardener? I haven't looked in a while, but when I looked in the past I could only find the more tropical species. It sounds like the perfect poultry feed and mulch, and I'd love to get my hands on some.

Well silly me!  I now know what a Chinampa is!  It’s the island I built in my pond! Who’d have thought.....

Mark, it sounds like you have a pretty nice pond ecosystem in place. May I ask how large your pond is? Sounds like it's fairly good size to accommodate all those species so well.

Mathew Trotter wrote:A chinampa is on my list for our pond, but it's a long ways down. Did you do something to reinforce the cinder blocks? . . .  I'd be paranoid about part of the wall collapsing and losing all of my soil into the pond.

My husband had the same concern, but, my project, my way :) I did not reinforce the bricks, simply filled them with the same fill dirt we took out of the pool. I acknowledge it's an experiment, and so subject to failure. But, it's only two cinder blocks tall, and there are no water currents to exert extremes in pressure. So far so good.

As far as patching the pond... do you really need to? Especially if you're adding gray water? If the pond is completely impervious, then it won't do much to hydrate the surrounding landscape (without actively removing water with pumps or buckets of whatever.) Personally, I'd want to slow water down, but not stop it completely (unless it were being stored for drinking.)

I've thought the same thing, in fact, I'm pondering planting something behind that crack that would benefit from the moisture. I'm also thinking we should include a diverter valve in the greywater filtration system, for times when we have lots of rain.

Janet, :)

Leigh Tate wrote:Mark, it sounds like you have a pretty nice pond ecosystem in place. May I ask how large your pond is? Sounds like it's fairly good size to accommodate all those species so well.

Nope, it's tiny, only abut 200 gallons. The pond part is about 2.5 feet deep and then there is a little stream area about 10 feet long and a few inches deep and a little water fall at the top.  A pump runs all the time and keeps the bottom of the pond and the stream/waterfall part from freezing. In the stream there is lots of wild mint whose roots are apparently pretty good at cleaning the water, I have to remove big gobs of it a couple times a year to keep the roots from clogging everything up. The pond has water lilies which used to be well behaved but since my big Ash trees died the pond now gets full sun and the lilies exploded and completely cover the surface so I have to trim them back some so I can see my fish.  Sometimes I stick sweet potatoes in the stream part in the spring and they grow massive vines and mats of roots.  

Rotted plants and leaves build up and I have to catch all my fish, drain it and clean it about once every two to three years. I do that in the spring because if it's done in fall the frogs don't have anyplace to sleep. The pond is directly outside the kitchen windows and I theorize that the bugs attracted to the lights and fall in the water is mostly what the fish eat because I don't feed them. They frogs too are often heard bouncing off the windows. Did you know you can't feed frogs? If it ain't moving it ain't food as as as a frog goes. But if it is moving it is, one time I came home and big frog had a little bird hanging out of it's mouth. The frog was obviously exhausted from trying to either spit the bird out or swallow it. The bird didn't look too good so I cut it's head off and the frog, bird head in mouth, disappeared in the water.

When the toads come to do their thing, they are LOUD! There is generally a dozen or more small, man toads at a time and just two or three bigger woman toads. Competition is fierce! And just as the frogs will try to eat anything that moves the toads will try to hump it, that includes your hand if it gets too close.  Eventually the girl toad picks out someone she likes and he latches on and they swim around like that for hours or days, heck if I know. Next thing you know the toads are all gone and the pond is full of gelatinous strings of toad eggs.

Like I said frogs will eat anything that moves , wasps, bumblebees they just flat don't care. The woman and I argued over planting too many flowers close to the pond, I got tired of watching frogs eat all those butterflies. I've seen them strike at hummingbirds but never catch one, dragon flies also are good at evasion but sometimes not good enough. This pond is apparently paradise for frogs, all they go to do is sit there and have everything come to them, fat lazy frogs. My take on it is they can just go out and hunt a little if they want to eat. Sometimes they do. On a rainy evening at dusk its an exodus of frogs hopping away into the yard to do frog stuff. Next morning at dawn they all come hopping back in. One time we were eating breakfast and big shadows flashed across the window, a great blue heron dropped down and gobbled up at least two frogs before I could get out there and scare it away.

Big frogs will even eat other frogs. The biggest frog each year is Jabba the Frog and the second biggest is Attila the Frog. If they commence to eating too many little frogs they get evicted to the farm pond up the road. It's half a mile away but sometimes they come back. One time I found baby snapping turtles in a compost pile so I put them in the pond and the frogs ate them too. STUPID frogs!

I think when it comes to water, if you build it "they will come"

Leigh Tate wrote:

I've thought the same thing, in fact, I'm pondering planting something behind that crack that would benefit from the moisture.

I'd be a bit cautious in your choices or the roots me decide to invade and expand the crack. An Arbutus tree that Mother Nature planted near our pond did that and it was a bad enough crack I had to seal it for the sake of the frogs. A Eucalyptus tree near our septic tank stuck roots between the tank and the lid, but the tank is far enough underground that the slight lift to the lid isn't a problem in that situation. It never fails to amaze me how small a crack certain roots will invade and expand.

Mark, thank you so much for sharing about your frog pond. Very interesting to read about and I love the pictures. It's beautiful!

Jay Angler wrote:I'd be a bit cautious in your choices or the roots me decide to invade and expand the crack.... It never fails to amaze me how small a crack certain roots will invade and expand.

Jay, good point. I will definitely keep that in mind when I get to where I'm ready to consider what to plant there.

Why not, fix the crack, direct the gutter water into the pond, collect as many different wild plants as you can from lakes where they are abundant in large quantities. Canooing or walking past rivers can get you so many different plant-types. All these different plants, if you get them in a plastic bag will carry with them microbes, fungi, insects, microscopic snales, creatures and eggs. This will make for a much more stable eco system, which can throw anything at any circumstance created.
What you're proposing now, using the gray water after filtering will still contain a lot of nitrates and phosphates, which in an unbalanced system are going to build up. You can't get rid of them, because the die off will create a mud layer full of nitrates. It can become anaerobic which leads to algae blooming which leads to your plants dying, which leads to more oxygen robbing and food for algae to kill off more plants.
If you fill the thing, you won't have to look at the tiles.
You can still be able to use the water for plants. Even better, because it will be warm and enriched by plants creating oxygen and so on.
If you manage to keep your current system and have the overflow fill the pool you can still have most of your water you like to have. But you could also chose to use this reservoir to pump it into the pool in summertime. Cooling it which the animals will like.
I've put some fish in my pond as babies, turned out to be roach or something. They eat plants, but only after the water temp reaches 15 degrees. I've got frogs, but hardly ever eggs of frogs. Females know not to waste their eggs and go elsewhere. My feeling is they're old bachelors and younger dudes gaining strength to go for it later at the place where the females go. I might completely make this up, but they were much louder when there were no fish in and females were to be called. Now why bother? Still they venture out at night getting rid of young snails. My house garden is next to the pond, so easy to scoop up water with a watering can.
It's just a small pond, forgot how many liters.

This is just all based on what I would like to have so might not be at all what you have in mind.
I know recycling and or making use of grey water is sometimes a permie goal but I wouldn't want anything to do with it in a context like that. I might use it to water shade trees or something  but nothing else. I haven't studied it either so don't really know what I'm talking about regarding it. It just spooks me a little and lacking knowledge I would just avoid it completely.

Also just based on what I like, if I had it to work with I would fill the deep end back in so it was only around 3 - 4 feet deep all over. That's just me and my paranoia in wanting it to be a little safer, especially for kids to play in.  Then I would go to one side or another or maybe all the way around and build a small berm, just a few inches, maybe a foot high. Just enough to raise it above the rim of the pool and an area at least twice the size of the pool.  Next I would get a large piece of that FDA approved grade EDPM pond liner and cover the whole thing, that might not be especially permie either but it's what I would do.

Now the fun could start, gathering up pretty rocks and driftwood and stuff to decorate it with. I don't know if I would completely fill the perimeter area with clean gravel or use pots filled with clean gravel to plant water loving plants in. I might go with the pots as it easier to clean the overall area or move or change plants as I saw fit. I've found in my little pond that actually almost anything, not just water plants will grow if potted in clean gravel and set in the little stream area.  Using pots, rocks, wood or other decorations can also give instant height to the plants.  

And unfortunately I can't think of a way around having a pump, so I'd get one big enough to cycle the volume at least once a day and run a hose from the deepest part into the filter area making sure it channels through the entire area before pouring back into the pool. If possible I would channel rain off roofs or even the ground into it.

Then the real fun would start, collecting up fish and plants from my neighborhood and turning them loose. I'd certainly have some water lilies and maybe some lotus, who knows what else.  I love fish and have had aquariums since I was a little kid so it would be a tough choice for me to decide between native fish and more colorful "troipical" fish. Or maybe a combination, you have to be careful mixing fish species from differing geographies but with some research it be done. Frogs, turtles, snakes and various other local critters will move in on their own.

OH! and I'd probably get a pet goose or two and give them silly names like Stella and Bob and I'd feed them so much they'd be too fat to fly so all they could do is swim around and hiss at people trespassing in their space.   That's probably not very permie either but o'well. Not that Stella and Bob generally silly names but they are geese.

Anyway, I'll keep a close eye on tis thread to see how your project goes, whatever you decide I hope you have lots of fun with it!

Hugo, your pond is beautiful!

Hugo Morvan wrote:What you're proposing now, using the gray water after filtering will still contain a lot of nitrates and phosphates, which in an unbalanced system are going to build up. You can't get rid of them...

The plan for my greywater filtration system is to utilize plants to deal with that, such as iris, taro, canna, pickerel rush, and watercress which quickly take up nitrates and other nutrients. My water testing kit will be able to verify how well that works. Not sure about the phosphates, though. They've been banned from soaps and detergents here for a long time, and I only use greywater safe products for anything that goes down the drain. What other sources of phosphates are there?

Why not . . . collect as many different wild plants as you can from lakes where they are abundant in large quantities.

I would love to be able to do that, except there aren't any public domain wild areas near where I live. Everything is either privately owned, or protected from harvest and collection by state and federal laws. If I ever meet someone with a private pond who would give me permission, I'd readily ask.

Mark Reed wrote:I know recycling and or making use of grey water is sometimes a permie goal but I wouldn't want anything to do with it in a context like that. I might use it to water shade trees or something  but nothing else. I haven't studied it either so don't really know what I'm talking about regarding it. It just spooks me a little and lacking knowledge I would just avoid it completely.  

Mark, caution is always a virtue, I think. However, (everyone), please note that I haven't gone into detail on the greywater idea yet because it will be months before the idea can thoroughly researched and a plan finalized. Also please note that the idea is not to just dump greywater into the pond. It must go through a filtration bed first. From my preliminary research, I understand that the combination of soil and plants creates an effective filtering process to remove excess nutrients and purify the water. This is the basis for numerous ideas for filtration beds out there. How well they work, I don't know, but acknowledge that any such system will require testing the water before implementing. However, all that is quite a few steps down the road.

Thank you Leigh Tate for the compliment.
It's better if no phosphates come in , so if it's not in your waste water it can't come in, i'd say except if it somehow gets in in the filtering system.
I've helped build a natural swimming pool and studied the book "How to build a Natural Swimming Pool" by Wolfram Kircher and Andrea Thon, university people who really study this. Where we did the natural swimming pool, they wanted to do the same as you are planning on, filtering the greywater with a lot of helophytes. They will oxygenate the substrate their root systems are in and take up quite a lot of nutrients, but bacteria will still flush into your pool, carrying nutrients in them. Overtime it will build up.
Somewhere in this book they adviced against it. It took me a week to study it, rattling up all that stuff from chemistry in the back of my head, and i'm not planning on doing that again. They adviced against all sorts of water entering except rain water, because it is so neutral and lacking in nutrients.
I just pass it on, maybe i assume wrongly you'd like something clear people would love to swim in.

It's a shame you can't get plants from the nature where you live, they would love a change of thriving in a new environment where they'll be admired. It looks like i advocate plundering nature the way i've worded it,in my previous post, but i never will or have. One plant or bit of a plant will grow hundredfold in a season when happy in it's new environment. If the government has decided it's illegal, then make sure one bit of plant doesn't accidentally got stuck in a boot or canoe, because that would be breaking the law.

Hugo, thank you for that, and the resource!

No, I'm not interested in using it as any kind of swimming pool (natural or otherwise) or for human use, other than to enjoy observing the pond life that dwells there!

Leigh Tate wrote:

Rob Griffin wrote:Not to sure how permie “flex seal” is but worked.  I built a Bill Mollison herb garden (from his permaculture book) for my mom probably 30 years ago with the small pond at the bottom of the spiral but I never could get it to hold water.

Rob, it doesn't sound very permie, does it? I believe there are threads about sealing ponds here in the forums, but I'm guessing it would be for dug, mud bottom ponds. I do know pigs can be used to seal mud, but I don't know exactly how.

The little pond at the end of the herb garden spiral from Bill Mollison’s book was not that big, maybe 25 gallons, 3 feet in diameter.  I had a good chuckle thinking about trying to train a pig do use its front two legs to just jump up and down in it to try to seal the bottom.

Spring is here, so I wanted to do an update.

Observations - for March 2021

Water. The water in the pool has cleared all the way to the deepest end!

So exciting to see how the water has cleared! The diagonal reflection is my clothesline.

You can see the layer of leaves on the bottom. This is where the frogs hide. When we come up to the pond on warm days, we see frogs jumping off their sunning spot and diving under the leaves.

Plants. The duckweed has pretty much been splashed out of it's holding pen from rain, but I still see it scattered here and there. I'm curious as to how much it will grow once it warms up. I was also able to find the hornwort I added last fall. It's still dormant, but I was pleased that it had grown quite a bit from the sprigs I bought at the pet shop.

Spring Planting. I'm just getting started on this.

My pond lilies arrived the other day! These are Nymphaea odorata, aka hardy water lilies.

Seeds for the chinampa.

You can see in the above photo that the soil in the chinampa has settled a bit from winter rains. But it's still there! I will start planting it with cardinal flower and blue flag iris. I plan to start a tray of seeds this afternoon.

Everything I'm planting here is chosen not only because they will benefit the pond and pond life, but also because they are edibles and/or medicinals.

I have other things I'm interested in planting, but this is my start for spring. Hopefully, I'll have more progress to report soon.

I have used bentonite clay to seal leaks in my pond it worked pretty good on the bottom,  You may want to use lime and then cover it with clay for the side.  

Thanks Nick. If the water level drops pretty low during our summer dry spell, we may try that.

Leigh, I love your pond adventures, looks like my recent aquarium-terrarium discoveries, on a slightly bigger scale.
I feel like it will be the "year of the water" for me this season.
I'm planning to make a small pond like Mark's lovely setup.

Mark Reed wrote:OH! and I'd probably get a pet goose or two and give them silly names like Stella and Bob and I'd feed them so much they'd be too fat to fly so all they could do is swim around and hiss at people trespassing in their space.   That's probably not very permie either but o'well. Not that Stella and Bob generally silly names but they are geese.

I love your love for pond fun! Of my aquatic critters only one has a name for now; the male guppy, Pablo. I placed an old book about Pablo Picasso behind the aquarium, to hide the cables, and he got his name by swimming in front of it.
Of water plants, duckweed seems to be great at pulling excess nutrients and stuff, and it's a nice mulch. In my terrarium, it invites springtails onto the water; they float anyway, but they seem to be more attracted to jumping on the duckweed, and then guppies hunt for them.
I now have two aquariums, and plants grow much faster in one of them... I'm not sure why. It's a little older than the other one, so maybe it just established itself better.

Flora, I love the photo of Pablo. So handsome!

That's good to know about duckweed. Somewhere I have a list of everything it can be used for - good stuff!

Beware of patching the crack. It is probably allowing the water pressure to equalise between the inside of the pond and the surrounding soil. If you reseal the pond you will need to have enough water in it to ballast the structure when there is a heavy rain and the soil around the pond become waterlogged. At that point, the pond will tend to float up and you will never get it back down again.

A good discussion on ponds.  I have a small but deep pond where I dug a hole with my small backhoe to investigate the soil horizons.  Found out that I have wet clay that actually fills in the hole through capillary rise.  It is starting to get some life in there and I expect it is too early for mosquitos but I will go get some goldfish to see how they do.  I like the Chinampa idea and will see if I can create a small sloped area and allow small animals, insects, birds to get some fresh water.  

Thank you so much for posting this.  My husband always wanted a pond, and I vetoed it thinking it would grow mosquitoes and be to much trouble.  Between reading Build a Better World in your Backyard, and this post, I'm changing my mind.  It won't happen right away, but there may be a pond in our future.
This is a little off topic, but one of my favorite memories of my middle daughter is she was about 3, wearing little overalls, you know the ones with the tiny pocket on the chest.  I say ok guys it's getting dark time to go in.  She slaps her hand by over the pocket.  What do you have in your pocket Sara?  Nothing.  Let me see.  She puts her hand down and I see a couple of toads.  Sara the toads have to stay outside.  No, they are my friends.  Sara your friends don't like the house, they are happy outside.  She thinks for a minute, and pulls a toad out, then another, and another....  I can't tell you how many toads she had in that little pocket, but it was a lot.  Strange enough they are hopped away seemingly ok.  It was one of those mom moments where I wanted to die laughing, but needed to let her know it might hurt the toads to put them in such a small space.  She still loves toads.  Stopped to take a picture of one not to long ago, she is 22 now.  Yes we would probably all enjoy a pond.  Thanks again. Look forward to your continued posts.

Earle, we've been discussion the pool walls and pressure from the soil. Hadn't thought about the water; something to look in to.

Dennis, who knows? The goldfish may eat mosquito larvae! I hope you'll start a thread of your own in the pond forum and share how it goes.

Jen, thank you! Your comment made my day! :)

I love the story about your daughter. Those kinds of memories are truly precious.

I do have a tiny pond in my front yard. There aren't many frogs there (I only saw one once). I used a plastic toddler playing pool (or sand box?) to keep the water in, because my 'soil' is just sand. But now I have an allotment garden plot, which is on the more peat-boggy side of town, I want to try and make a small pond there without any lining ...

Spotted today - 4 frogs enjoying the sun.

June 1st update.

Exciting news - dragonflies!

Dragonflies have become regular visitors.

I don't recall seeing these last year, but this year we have quite a few. I counted a dozen the other day, at least two different kinds.

I'm pleased to report that my pond lilies are doing well. I planted them in March, and they are growing new leaves.

Nymphaea odorata, aka hardy water lilies, with kudzu cascading over the side of the pool.

The frogs are too big to jump on the pads, but they like to rest their front legs on them.

The hornwort is growing really well too. It's hard to see because the water is still murky from recent rain, but if you look in the center of the photo, you'll see them floating just under the surface of the water.

The hornwort grew quite a bit over winter.

My duckweed seemed to have disappeared over winter, however. So I bought another 500 plants.

The duckweed corral seemed like a good idea, but rain splashes it out as do frogs jumping out of it.

None of my blue flag and cardinal flower seeds germinated, which was sad. So I bought five blue flag irises to plant in the chinampa.

Blue flag irises.

Hopefully, they'll do well.

And of course the frogs.

Happy frogs.

!!!

Last year, I first saw tadpoles in June. This year in June there were none. I was disappointed and wondered why. Now, I see lots of tadpoles! June was unseasonably chilly for us, so I'm thinking temperature may have had something to do with it.

Tadpoles

I'm also seeing some little frogs, about the size of a quarter. Lots of frog song at night or when it starts to rain. Some of the frogs are quite large. One has a deep song, just like what my dad told me were bullfrogs when I was a kid.

Also spotted

Water spider

This is such a great project!  And seeing you take on such a large experiment makes me feel more brave about a little backyard pond.  Except for that water spider.  That thing may squash all of my courage!