A few years ago I wrote a post explaining how to make a container pond in a stock tank, and many readers have since written to tell me they’ve made their own ponds by following my instructions. I also get a lot of questions about how to take care of a stock-tank pond throughout the year, so last fall I wrote a follow-up post about winterizing my pond, and today I’ll show you how to clean a stock-tank pond in preparation for summer. Keep in mind that all my pond information is relevant for zone 8b; those of you in colder climates should consult a local pond expert for more information.

The picture above shows just how ugly my stock-tank pond looked last weekend, after a few winter freezes and the big leaf drop that happens in mid-March as the live oaks shed their old leaves. Not pretty! With freezing temps behind us and summer right around the corner, it was time to clean the pond.

First I put on old clothes that I didn’t mind getting muddy. Next I unplugged the pump that runs the spigot fountain. Then I reached in and pulled out all the plants. Have I mentioned that pond plants grow like they’re on steroids? This is my ‘Colorado’ water lily after a season of growth. It’s grown right out of its plastic container and produced an entirely new plant, connected to the old one, outside the pot. Look carefully on the lower right, and you’ll see the rim of the black plastic pot. The mass in my hands is the new, unrooted lily.

Once all the pond plants are out of the pond (place them under wet newspapers in the shade if the day is hot; they should not be allowed to dry out), use a sturdy net to clean the surface of the pond of leaves, rotted plant material, and other debris. Then sweep the bottom of the pond with the net, lifting out decomposing plant matter and putting it in the compost pile. Be careful not to scoop up or accidentally discard your fish. Once you start netting the bottom of the pond, the water will get cloudy with silt, so you’ll need to examine your net carefully each time you dump it out. Alternatively, you could net your fish and put them in a clean tank filled with pond water while you clean, but I never do this and still end up with what seems like all my fish.

Once the pond is mucked out, it’s time to divide the plants. Pond plants need dividing every year because of their aggressive growth. The nice thing about this is that you can furnish your pond-loving friends with divisions each year. Of course, next year they’ll be looking for someone to give their divisions to as well.

If you can slip or shake your plant loose from the plastic pot, great. Sometimes, however, the plant just won’t budge. In that case, I use a hatchet to split the side of the pot, cutting the plant loose and exposing a very root-bound plant.

Then I use the hatchet to cut through the root-bound plant, dividing it in half. You could also use a plant saw to divide the plant, and maybe that would be safer than a hatchet. I am quite careful about where I swing that blade.

The hatchet goes through all that mess as if it were soft butter.

Here I’m dividing a slightly less messy ‘Helvola’ water lily. Make sure you divide so that you see stems and roots in each piece.

Chop, chop. I got three divisions out of this one.

Place your divisions, ideally, in solid, plastic pond pots with no drainage holes. However, if, like me, you neglected to buy enough pond pots, you can use regular nursery pots. The plant will probably send roots out through the drainage holes, but since the pot sits in a metal tank, the plant can’t really escape anywhere.

You’ll need to fill in around the divisions with soil. Pond plants like to be planted in heavy clay. Don’t use regular bagged potting soil, which is too light and will float out of the pot. I just go out in the garden and dig up some clayey soil, of which I have plenty, to fill in my pots. If you don’t have clay soil in your yard, heavy potting soil can be purchased at pond stores. Hill Country Water Gardens in Cedar Park, for example, sells a 50-lb. bag for $5. I’m sure you don’t douse your lawn or garden with chemical fertilizers or pesticides, but if so, you shouldn’t use that soil in your pond.

Here’s a ‘Helvola’ division all potted up with lots of growing room. Next step: top your plant pots with a layer of clean gravel to help keep fish from nibbling the plant down to nothing and to keep mud from clouding your water. I press one fertilizer tab for pond plants into each of my new divisions and then place them back in the pond. Water lilies go on the bottom of the tank; marginal or bog plants go on top of overturned pots or piles of bricks so that they sit near the surface.

The final step is to purchase new underwater cleaner plants, which are essential for keeping your pond free of algae in the summer. I use 8 bundles of anacharis in my 700-gallon pond. Place the bundled anacharis stems in pots of clean gravel (no need for soil) on the bottom of the pond. The gravel holds the bundles in place.

Take this opportunity to clean out the filter in your pond pump. Remind yourself that you really should stay more on top of cleaning your pump’s filter. Then put it back in the pond and plug it in.

Voila! Your pond is clean and ready for summer. Enjoy!

This is part 3 of a 3-part pond series:
Part 1 — How to make a container pond in a stock tank
Part 2 — Winterizing a stock tank pond
Part 3 — How to spring clean your stock tank container pond

All material © 2006-2013 by Pam Penick for Digging. Unauthorized reproduction prohibited.

Yes, I do in fact have a water lily blooming at the moment. January was mild, and it remains beautiful in Austin this week, with sunny days and highs in the 70s, and the ‘Colorado’ water lily in the stock-tank pond has responded with a pale apricot version of its usual salmon-pink flower. Which only reminds me that I need to get in there soon and muck out the bottom of the tank and divide the lilies and other pond plants.

Back at the castle…and regally unchanged by the seasons, Queen Victoria agave (Agave victoriae-reginae) looks handsome in her deep-green robes with white piping.

And the succulents in the cinderblock wall-planter are still looking pretty good, unfazed by the several freezes we’ve had. I do throw a sheet over them when a freeze is predicted, and they enjoy the shelter of a live oak canopy and close proximity to the house.

So, is spring coming early to your garden, or does winter still have a firm grip?

All material © 2006-2013 by Pam Penick for Digging. Unauthorized reproduction prohibited.

“How to make a container pond in a stock tank” is consistently one of my most-viewed posts, and many readers have written to tell me they’ve made their own ponds by following my instructions. Recently two people asked me how to winterize their ponds, so I decided to explain how in part 2 of what will be a 3-part series. This spring I’ll end the series by showing how to divide pond plants and prep the pond for summer growth.

Winterizing a stock-tank pond is actually quite simple in Austin’s mild-winter climate. It involves these six steps (3 of which are really inactions):

Scoop fallen leaves
Use a net to scoop fallen leaves off the surface of your pond several times a week to keep them from sinking and decomposing in the bottom of your tank. My pond is situated near live oaks, which don’t lose their leaves until March, so my biggest leaf clean-up occurs then.

Don’t divide pond plants yet
Your water lilies and other pond plants likely grew vigorously over the summer, and you may have noticed that some of them are literally bursting out of their pots. It’s amazing what these plants are capable of. By fall, my water lilies are no longer blooming as much, and their leaves may be mottled and a bit mushy, but at the bottom of the pond they are vigorous monsters, with roots creeping out of their pots and possibly supporting a fully formed baby plant. Marginal plants that live at the top of the pond, like dwarf papyrus, may have reproduced as well, with new plants rooting from fallen stems floating in the water.

It may be tempting to divide and repot your pond plants now, since they are clearly trying so hard to reproduce, but don’t. The first hard freeze will likely turn your lilies into mush, causing them to die back to the roots. That’s fine. Just pull out any mushy stems and rotten leaf pads; they should easily come loose when you lightly tug them. In our typical mild winters, your lilies may retain leaves and even bloom occasionally through the winter. Enjoy!

Drop cold-tender plants to the bottom of the pond during hard freezes
Hard freezes won’t hurt hardy water lilies (tropical lilies may need to be overwintered indoors). But they might kill your cold-tender marginal plants, which live at the top of the pond. I’ve lost dwarf papyrus and pond crinum in hard freezes, for example. So now, when a hard freeze is predicted, I drop the pots to the bottom of the pond until the air temperature is above freezing again. In central Texas, hard freezes rarely last longer than a few hours, so I’ll pull the plants back up to their perches in the afternoon. But if we get a real doozy of a cold snap, I’ll leave them at the bottom for two or three days, and they’ll be fine—a little mushy, perhaps, but alive.

Turn off your bubbler pump or fountain during hard freezes
If you have a pump in your pond, turn it off if a hard freeze is predicted unless it’s powerful enough to keep the water from freezing. I don’t take a chance, and simply unplug mine during freezing weather. The pump itself sits a foot under the surface, so it’s not going to be damaged even if the surface of the water ices over. If your pump sits right at the surface, then drop it to the bottom of the pond or remove it so that water is not able to freeze inside it.

Stop feeding fish
I rarely feed my goldfish and gambusia fish, and they survive just fine on algae, mosquito larvae (they keep the tank clean of these pests), and my underwater plants. But if you regularly feed your fish, stop when the weather turns cool. The fish will go into a semi-dormant state over the winter, and they won’t be able to digest food properly until the water warms up again. Just let them be.

Stop fertilizing your plants
Most pond plants stop growing in cooler weather, so stop using fertilizer tablets now. From late October to early April, don’t fertilize. Resume feeding after you’ve divided your plants in spring (which I’ll cover in detail next spring).

Remember: Prepping your stock-tank pond for winter may require more extensive measures if you live in a colder climate than I do—including, perhaps, overwintering your fish indoors, unplugging your pump, and even emptying your pond for the season. The winterization that I do is sufficient for my 2-foot deep pond in my zone 8b garden.

This is part 2 of a 3-part pond series:
Part 1 — How to make a container pond in a stock tank
Part 2 — Winterizing a stock tank pond
Part 3 — How to spring clean your stock tank container pond

All material © 2006-2012 by Pam Penick for Digging. Unauthorized reproduction prohibited.