Pond Maintenance

Maintaining water gardens, koi ponds, and other water features is relatively easy compared to other types of gardening or landscaping. Mowing, weeding, mulching, or irrigating simply are not needed. Regardless, some attention will keep the water clear, the plants thriving, the fish healthy and the pond owner happy! Following are the key maintenance steps and the tools you need to accomplish them.


  • Waterproof Gloves (optional)
  • Pruners or Heavy Scissors
  • Large Knife (for root division).
  • Net, a sturdy frame and handle are a must.
  • Skimmer Net
  • Pump and Tubing for draining, water changes, etc.
  • Garden Hose and adjustable Nozzle
  • Outdoor Extension Cord
  • Shop Vac, for clean-up and final draining when needed.
  • Wheelbarrow, for hauling and debris removal, the plastic styles are ideal.
  • Plastic buckets and tubs, a good variety will be handy for many purposes.
  • Pond Vacuum (generally not needed if pruning and skimming are done regularly)
  • Water Quality Test Kit, a simple, accurate one to use if fish show distress


    First learn and understand The Nitrogen Cycle. This is the natural process that allows the pond to break down organic waste and convert it to a usable plant nutrient. Typically small lined ponds create too much organic waste leading to poor water quality and/or algae blooms. Put simply, keeping organic waste to a minimum will keep the pond "balanced" and clear. So what is the source of this organic waste? Three basic sources are; fish waste, decomposing plant matter from within the pond, and debris that enters from outside the pond, such as leaves. This makes pruning pond plants, surface skimming, regular filter maintenance, and controled fish feeding critical for a "balanced", beautiful pond.


    Aquatic plants grow quickly and new growth forces old growth to yellow and decay. Weekly (minimum) use pruners or scissors to clip any old discolored, damaged, or spent foliage, flowers, stems, etc. Be thorough since this will become the majority of organic waste in most ponds. Well planted ponds over 100 sq. ft. can produce as much as 50 lbs of plant debris in a week! Even so this will only take about 30 minutes to accomplish.


    Waterlilies and Lotuses in particular, appreciate regular feeding. Use Tablets designed for aquatics. Long term tablets are appealing though standard ones applied monthly or bi-weekly remain a favorite of purists and produce optimum results. Simply push the tablets into the soil per label rates. Ideally every 14 to 21 days for lillies, 10 days for lotuses, and bog plants as needed. Begin fertilizing in spring with appearance of new growth until 4 to 6 weeks prior to normal frost date.


    Hardy Aquatic Plants require root division and re-planting into fresh soil once every 2 to 3 seasons. Some varieties prefer annual transplanting. Regardless, this task ensures peak performance of the plants. The ideal time to divide is early spring since this will allow the plant to recover before the bloom period. Exceptions are Irises which should be divided in mid to late summer after they have flowered, and Lotuses can only be transplanted in the spring before mid-April. All other plants will survive divisions done before Sept. 1. Aquatic plants grow best in a heavy topsoil with a little clay. Do not use lighter mixes that are appropriate for non-aquatic plants. The final step of planting/transplanting is adding a layer (1" or less) of rinsed pea gravel over the soil. Fertilize all aquatics with initial planting except lotus which should not be fertilized until 1-2 leaves appear.


    Most Pumps are submersible and operate in the pond. Some pumps work outside the pond with a pipeline to intake water. Regardless, locate the intake point on the pump, or in the pond, (it may even be the drain). Keeping the intake flowing clearly is critical to the performance and life of the pump. Leaves, algae and other debris can clog the intake, reducing the flow-rates which in turn overheats the pump and hampers the Filter and/or Skimmer. Use "solid-handling" pumps or Pump Protective Devices to greatly reduce pump maintainence. Pumps should operate 24/7 during the growing season then turned off when ice appears. Leave submersible pumps in the pond, below the freeze depth, and drain pump and pipe-lines of non-submersible ones prior to freezing weather.


    Proper maintenance of filters ensures their contribution to clear, healthy water. Conversely, under-maintained filters can ruin pumps and degrade water quality. There are four types of pond filtration; mechanical, biological, chemical, and ultra-violet.

  • Mechanical Filters generally need attention 1-3 times weekly depending on how dirty/cloudy the water is. The process typically involves removing and rinsing pads or similar media. The more frequently they are cleaned the better they perform.
  • Biological Filters normally require draining or back-washing" 1-4 times monthly. Never "over-clean" bio-media since this houses living, benefical bacteria, and always "re-charge" the filter with a Bacterial Supplement after maintaining.
  • Ultra-violet "UV" Sterilizers/Clarifiers need to be checked only occasionally for bulb performance. All have some type of port or opening to check for bulb illumination. Bulbs must be replaced within 12 months of continuous use, even if the lamp stays illuminated after a year the "UV" output is too minimal for effectiveness. Check the interior chamber for accumulated debris that may impact performance.
  • Combination Filters are very popular now and some sport all three types of filtration. Simply treat each component as described above. All filters (particularly "out-of-pond" types) and pipelines must be drained and/or protected from freezing conditions.


    Many modern ponds have Automatic Skimmers that require just emptying a collecting basket or net periodically. Frequency will vary dependent on many factors but remember these are essentially mechanical intake filters and "under-cleaning" could damage the pump. A hand-held "net" type skimmer is the other method of surface (or sub-surface) debris removal. Always make this the final step of any maintaining or cleaning process since this is a source of organic debris. Use a netting cover in the fall when rapidly falling leaves are difficult to keep up with.


    Generally speaking, properly stocked, "balanced", and maintained ponds stay free of excess algae, fish disease, pests and inferior water quality. If these do occur a wide array of products, medications, and testing kits are available. Healthy appearing plants, and particularly fish are confirmations of good water quality, regardless of water clarity, or any test results. Typically when living things in the pond develop health problems it relates something wrong in their environment, causing stress to their immune systems. Careful water testing should be performed prior to addition of any treatments. Follow instructions included in test kits. It must be noted that Overfeeding fish is the # 1 way that backyard pond environments are upset. The dilemma is obvious since many pond owners consider feeding the fish the most enjoyable part of the hobby. Fish feeding will require some discipline. Regardless, when problems arise "a little investigation goes a long way".