Plastic Ponds

Here’s the word on plastic ponds. Some of it is good, some not so good but it all depends on your situation.

The good news is that plastic ponds come in a variety of sizes so you can fit the smallest pond into a corner of a small garden and you can have a water feature in your garden.

The bad news about this construction method is that while the hole is easy to dig, it is not so easy to get the pond level.

A Deeper Hole

The trick to this is to dig the hole about six inches deeper than you need to and then fill it back up with sand. Create a level surface from end to end and side to side with the sand. Dampen the sand to make it easier to stay in one spot and ensure not only that the bottom your pond is level, that it is flat as well so the pond will sit securely without rocking. Rocking in the winter is not a good idea when the pond is full of water and Mother Nature wants to move it around.

The sand will create a level surface and will also prevent rocks attacking the bottom of your pond when the frost throws them up. You’ll need to dig the hole about a foot wider and longer than your pond for the same reason. You’ll be leveling it from end to end and side to side to get it right. Then you’ll be backfilling the sides with sand to support those sides and the weight of water.

The good news is this is faster and easier than digging a hole for a liner type of pond.

The bad news is that this kind of pond means you have to make decisions about what you’re going to grow in it. Preformed plastic ponds are small. This means they won’t support lots of fish, waterfalls, lilies and other plants. If you try to cram all these things into the pond, you’ll have algae problems like you don’t believe and you’ll be really unhappy and swear that ponds are a pain in the anatomy.

Ecological Balancing Act

Small ponds are harder to balance ecologically but it can be done.

Understand that the larger the pond, the easier it is to garden in. And the biggest plastic pond is still a very small pond in ecological terms.

I’ve had several of these but I installed them in my garden for specific purposes. One was really tiny (about three feet long) and I put it under a crabapple tree for reflective purposes. I also used it to keep some aquarium fish in for the summer. It was way to shaded for lilies and a water pump would only have stirred up things. I added a lot of floating oxygenators to keep it clear and this worked. Not only that but in the fall, I had bumper crops of fish that would breed away all summer.

I use a slightly larger plastic pond (about 7 feet long) out in the sunshine as an exclamation mark in my perennial border. It was in an area that I wanted to sit and stare at the garden so I put a pond there as well. It served as a watering hole for all the frogs that kept down the pests in the garden and birds used it as well. It was too small for a pump so I used oxygenating plants and a massive tropical lily to cover the water surface and prevent algae. It also was home to some small aquarium fish that didn’t bother the plants (they bred like crazy down there) but did control mosquitoes and ate all the surface algae they could find.

Bigger Is Better

So what would I suggest? Get the biggest one you can afford. Get the heaviest plastic you can find (most of them are OK but there’s a few out there that are really flimsy like a kid’s swimming pool). Don’t bother with a pump and filter; use oxygenators and lilies instead to keep the water clear. If you want a pump, don’t waste your money on lilies because a pump in a pond that size will likely jiggle the lily around so much it will be unhappy and won’t give you your money’s worth on flowers.

Fish & Plastic Ponds

Use small goldfish if you want to see the fish and be prepared to give them all away every year because otherwise you’ll wind up with way too many big goldfish (big goldfish make little goldfish) or use a fish like a rosy barb like I do to control mosquitoes. I don’t feed them by the way, they’re happy on what lands in the pond and the algae that grows on the side.

Or, spend the bucks and build and install a liner pond that is large enough to do plants, fish and water movement. Check the links to the left for construction tips.

Plastic ponds are best suited for specific uses in the garden but you combine those uses (fish/plants/pumps) at your gardening peril. Contrary to what the sales guys will tell you; it is tricky to do all three and keep them all (not to mention you) happy with the outcome. There's just too many variables to balance in a small plastic pond. Sorry to have to burst a bubble but it is better to hear this from me before you spend your money! :-)

If you've got a small plastic pond, then the suggestion is the same - simplify and decide to focus on one of plants, pumps or fish.

Do you have a question about plastic ponds


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