Spring and Summer Pond Care

“Greetings on this most exceedingly beautiful spring morning. A morning swollen with new life, a morning on which, if I had the voice, I would let loose with song. It's hard to believe just a few short weeks ago we were eating our cornflakes in the wintry dark. Now … I can see the golden glow of Apollo's chariot waiting in the wings, about to make its entrance. Winter's on the lam, no doubt,” so mused Chris in the Morning on KBHR, the radio station on the long- gone quirky television series Northern Exposure.

When winter does, indeed, go on the lam, it’s time to start thinking about getting your water garden ready for the warm months ahead. Like life itself, spring is a time of transition time for your pond. Days are getting longer, the earth is closer to the sun, the thermometer is rising, fish are increasing their activity and plants, including algae, begin their growth cycle.

Even the best-balanced ponds experience algae growth in the spring. It’s inevitable because fish begin producing nitrogenous wastes and aquatic plants have not grown enough to remove substantial amounts of nitrogen from the water. This natural event is no cause for alarm; in fact, a spring algae bloom actually helps protect fish from potentially high levels of ammonia and nitrite. But a little effort now can decrease water greening that may be unhealthy to pond life and unpleasant to the onlooker. Spring maintenance plays an important role in general pond health and enhances enjoyment throughout the growing season.

We recommend a partial water change as soon as weather permits. The amount of water removed may be as little as 20 percent if the pond was well prepared for winter, or up to 50 percent if there is an accumulation of dead leaves and other debris. A good rule of thumb is 30 percent. Complete changes should be reserved for ponds that contain no fish or plants, or those that have suffered major losses of fish and plants over the winter. Use a pump or siphon to remove the desired amount of water.

Move potted plants from the pond to a shady area or, in sun, cover with wet newspaper. Try not to stir up dirt and debris any more than necessary so the pond bottom remains visible. Using a fine mesh net, scoop along the bottom and edges to remove leaves, debris and dirt that have blown and fallen into the pond, creating a layer of muck. Be prepared for a mess. The dark, smelly, gooey substance contains rotted fish food, fish excrement, and decaying plant matter. Remove as much of it as possible. When warmer weather arrives this muck will decompose further, fouling the water and promoting fish disease as well as algae growth. The addition of a bacterial/enzyme product can encourage the healthy breakdown of the remaining small amounts of debris. The muck you remove can be used to fertilize plants around the garden or added to the compost pile. Don’t try to remove the moss-like algae growth you might find on rocks or on the sides of your pond. This algae has beneficial microorganisms that help balance the pond ecosystem.

Inspect your fish carefully. Look for any unusual behavior, injuries, swollen abdomens, or white or red flecks on the fins or bodies. If any problems are apparent, consult your fish supplier for treatment options.

While the water level is low, every piece of equipment should be inspected for wear and damage, including pumps, filters, lights and all cables, tubing and connections. Assess the overall condition of the pond liner or pre-formed pond. You may be able to patch smaller tears or punctures, but evidence of larger damage or degradation may indicate it's time to replace the liner.

Pay particular attention to electrical cords that may be frayed or cracked. At best, these will trip Ground Fault Interrupters or circuit breakers; at worst, they create a shock hazard for both fish and humans. Check the electrical circuit and be sure the GFI (Ground Fault Interrupter) is working properly.

Carefully inspect pumps. Look for housing damage which could result in electrical shock hazard or, in some models, oil leakage and intake blockage (which can reduce water flow and possibly damage the pump itself). If so designed, the pump should also be opened for inspection of the impeller.

Be sure there are no leaks in your plumbing. Look for stiff, kinked or ruptured tubing. Any constrictions or leakage will reduce the water flow available to fountains, waterfalls and filters. If you have used any clamps, tighten them now.

Filters should be cleaned of visible debris that will reduce flow or break down into algae-promoting nutrients. Even biological filter media may require rinsing if it has been stored dry or in stagnant water. Replace filter pads.

Now it’s time to work on the plants you removed and set aside earlier. Trim away dead foliage then divide and repot marginal hardies as needed. Heavy garden soil should be used to pot all water plants. Don’t use potting soil, compost, vermiculite, or perlite; they will float and foul the water. Soil should be added to a level one inch below the pot rim and topped with clean gravel to discourage fish from digging in pots.

Hardy lilies that have grown out of their pots should be repotted. Turn the pot upside down to remove the plant and dirt. Flush the dirt from the rhizome and roots with water. Use a sharp knife on a hard surface and cut off any brown and black roots and rotted areas from the rhizome.

If water temperatures are in the 40 degree F. range, rub fresh cuts on the rhizome with powdered charcoal to discourage rot. Separate side growth "eyes" from the primary rhizome and replant them. Hardy lilies grow horizontally and should be placed against one side of the pot at a 45-degree angle, with the crown above the soil so it has room to grow across the pot. Hardy lilies prefer at least one cubic foot of soil, but will grow in smaller pots. Growth is commensurate to soil area for root growth: the bigger the pot, the bigger the plant and, the bigger the show.

Fertilize plants using aquatic plant tablets and return them to their growing spots in the pond. Sink repotted plants into the water slowly to prevent release of soil into the water.

When your plants are all in place and you’re comfortable with the condition of your pond liner and mechanical equipment, it’s time to refill the pond. Ideally, a garden hose should be left to trickle new water into the pond over a matter of hours, or even days, to prevent a radical change in the pond's water temperature. This also allows for some escape of gases from tap water as well. If municipal water is used, a dechlorinator and chloramine remover should be used at the rate specified.

When the pond is full, resume circulation and filtration. As fish and other animal life begin to produce waste products, it is important to prevent dangerous buildups of ammonia and nitrites. For a small fish population, simple aeration and circulation may be adequate to support the beneficial bacteria that remove these two toxic compounds, but heavier stocking may require the use of a more sophisticated biological filter. If you have a waterfall or stream, watch the water level for several days. If it drops, look for a leak around the waterfall.

Newly-purchased fish (or fish wintered in indoor tanks) can now be introduced to the pond. Water temperature differences should be less than five degrees to reduce stress to fish. Be sure heavily fed fish from a warmer environment are not suddenly placed in a pond so cool that it shuts down their digestive systems. Other factors that are of concern include pH, ammonia, nitrite and nitrate levels, all of which can be easily measured with common aquarium or pond test kits.

Fish digestion is very slow at cooler temperatures. Don’t start feeding your fish until the water temperature reaches 55 degrees and then use fish food formulated for spring/fall. You can check to see if your fish are ready to resume eating by dropping a sinking pellet of food into the pond. If fish rush to consume it before it gets to the bottom they are totally awake and can digest food. Regular and growth food can be introduced when water temperature reaches 65 degrees.

When the weather gets warmer, steps should be taken to maintain your pond through the summer. Tropical water plants may be returned to the pond when daytime water temperatures reach 70 degrees and night temperatures do not drop below 50 degrees.

Fertilize marginal plants about every six weeks through the growing season. Lilies should be fertilized every three weeks, until early August. Tablet or pellet fertilizer for aquatic plants is recommended. Excessive yellow leaves or pads, few petals on flowers, or poor blooming can indicate a lack of nutrients. Prune and remove all dead leaves (pads) or flowers from the plant at the crown level, throughout the growing season.

Add water as necessary to replace amounts lost through evaporation. Remember to use a dechlorinator and chloramine remover at the rate specified if you add more than one inch of water.