Essential Backyard Pond Maintenance Tips for Every Season

A backyard pond brings plenty of tranquility to a yard, but it also requires a fair bit of maintenance to stay clean year-round. That’s even more important if your pond is a home for koi fish, who need a clean, temperature-regulated habitat to remain healthy. Use this list of year-round backyard pond maintenance tasks to ensure it remains an oasis for you and your fish both.

How Often Does a Pond Need Maintenance?

It seems counterintuitive, but a large landscape pond typically requires less maintenance than a small one. Smaller ponds are more prone to fluctuations in ecology and chemistry. However, weekly pond maintenance is necessary for all ponds, with more work at the beginning and end of the growing season in cold-weather climates.

Spring Maintenance Tasks

Spring is the busiest time for pond maintenance, as you’re coming off the dormancy of winter and prepping the water for the warm season ahead.

• Reinstall pump and filter.
• Combat any algae that has built up by applying fish-safe algicide and enzymes. Some gardeners find success placing a barley straw bale in the water, which releases compounds that naturally prevent algae growth.
• Top off the water level by trickling water at the bottom of the pond to avoid the buildup of salts and minerals.
• Skim leaves and debris.
• Add new floating and submerged plants once the water has warmed to 50ºF and all danger of frost has passed—this will keep algae in check.
• Begin feeding fish using a high-carbohydrate food to help them with increased activity.

Summer Maintenance Tasks

Summer is all about staying on top of the water chemistry, algae, and plant growth to keep the pond in healthy balance.

• Test the water chemistry weekly using a kit for ammonia, chloramines, and chlorine. An excessive amount of these chemicals will kill fish.
• Check filters and pump intakes weekly for clogs; clean as needed.
• Trim plants and remove dead leaves, flowers, and overgrown plants to prevent fast growers and plant debris from overwhelming the pond.
• Control plant pests to maintain healthy flora.
• Control algae with a long-handled bristle brush, rake, or pole.
• Add a fountain or bubbler to increase aeration for fish; hot water can be oxygen-depleted.
• Top the water level as needed—keeping the proper water balance and preventing salt and mineral buildup is essential. When water is required, add large amounts rarely and small amounts often.

Fall Maintenance Tasks

Leaf removal is an important chore year-round, though for most gardeners it ramps up in the fall. Too many can clog the filter and even suffocate fish.

• Skim or net falling leaves.
• Disconnect the water filter and pumps; drain and store inside. Drain water lines and fountains, using a siphon if necessary.
• Move nonhardy plants indoors. If your pond doesn’t freeze solid, move hardy submerged plants and hardy water lilies and lotus to the deepest part of the pond after trimming off the foliage.
• Reduce fish feeding and stop completely when the water temperature decreases to 50ºF.

Winter Maintenance Tasks

In winter, pond maintenance quiets down, particularly if you live in a cold climate. Your most important task is keeping koi alive, through providing pockets of open water.

• Float a pond heater in the water to ensure an area of open water for the fish to get oxygen.
• Do not feed koi in winter, since their slowing metabolism makes them unable to digest food.
• Float wood or a ball on the pond surface to absorb pressure from expanding ice.