Spring Pond MaintenanceAs the pond begins to wake up after its winter sleep a few simple jobs done at this end of the year should help get things off to a flying start as the weather warms up. Equipment which has lain unused since the autumn needs to be prepared for the new season and the pond itself will probably benefit from a few final touches before things get underway in earnest.

Spring is also one of the most difficult times for fish, which have been dormant throughout the cold and now need to adjust to the quickening rhythm of life as the water warms up. However, bacteria and parasites will also be present in the water and will themselves be starting to become more active, which can pose a threat of disease, particularly to any fish which have been weakened by the strain of over-wintering. In addition to the routine seasonal maintenance, the fish-keeper also needs to keep a particularly vigilant look-out at this time of year for the first signs of illness.

Year round pond maintenance is important, and we have guides for Spring. Autumn, Summer and Winter

Clarifiers, Filters and Pumps

With spring comes the return of the green water threat, so the pond’s ultra violet clarifier needs to be brought back into operation to counter the algae which cause it. As the UV bulb ages, its efficiency drops and less UV radiation is produced, so it needs to be replaced ideally each year. Spring is a good time to do this, since the clarification effect is most needed in the opening few months of the season, when the likelihood of algal blooms is at its highest. When changing the bulb, it is a good idea to check that the quartz tube it sits in is free of deposits or lime-scale – a dirty tube will also cut down the amount of UV hitting the algae.

Cleaning the bio-filter is another job for this time of year, paying particular attention to shifting any old sludge that has settled, so it does not get recycled back into the pond once you turn the pump back on. Be sure to use pond water or rainwater to wash the filter, rather than tap water, to avoid introducing chlorine and other unwanted chemicals into the system. If possible, it is often a good idea to try to time things so that you can run the filter for a week or two before the weather really starts to warm up and the fish become active, allowing the numbers of beneficial filter bacteria to build up.

If your autumn or winter maintenance did not include removing the pump, now is the time to lift it and clean it up – externally and internally – to ensure that the pre-filter unit is clear, the intake is not blocked and that the impellor is not fouled so that it can rotate freely.

The Pond

If large numbers of leaves have found their way into the pond or a thick layer of sludge is sitting on the bottom, it is worth either hiring a pond-vac or using a wide-bore tube as a siphon, to suck up the deposits and dispose of them, to avoid storing up problems for later. Left alone, this material will begin to decompose as the warmth brings increased bacterial activity – leading to the possibility of excess nutrients to drive algal growth, not to mention depleting the dissolved oxygen in the water. Although ponds generally look very clear at this time of year, testing the water before everything really begins to get going will give you a better idea of what sort of condition it is in and also alert you to any potential problems before they become significant.

Finally, once the danger of frost is passed, delicate plants which were removed from the pond or bog garden for the winter can be returned and any plants which need dividing should now be split and replanted in suitable baskets, using a good, low-nutrient pond compost.

With all the season’s routine maintenance out of the way, you can safely settle back and wait for the temperature to slowly rise and hopefully begin to reap the rewards of you efforts as the new growing season gets underway.

Spring time tasks for your pond

Clean pumps and filters

Give your pond pump and mechanical filter a good cleaning: A pond pump and mechanical filter are essential for keeping the water circulating and removing debris from the pond. Over time, these components can become clogged with debris and require cleaning to maintain their effectiveness. It is recommended to clean the pump and filter at least once a month or more frequently if you have a lot of debris in your pond.

Remove leaves and debris

Remove leaves or other debris that may have sunk to the bottom of your pond: As the water temperature rises, decomposing leaves and debris can release harmful toxins that can affect the health of your fish and plants. Removing these materials on a regular basis helps maintain good water quality and prevent algae growth.

Check your fish for any illnesses or wounds

Fish are susceptible to a variety of diseases and parasites that can quickly spread throughout the pond. Signs of illness or wounds may include redness, spots, abnormal behavior, or lethargy. Early detection is essential for effective treatment, so regular monitoring of your fish is important. If you notice any issues, it is recommended to quarantine affected fish and seek advice from a veterinarian or aquatic specialist.

Dividing and Repotting Pond Plants

Pond plants play a vital role in maintaining a healthy and balanced ecosystem. Dividing and repotting plants regularly ensures they receive the necessary nutrients and continue to grow healthily. While repotting, avoid using soil that contains a lot of organic matter as it can encourage algae growth and harm the plants. Most water plants grow well in sand and do not require fertilizer, except for water lilies which require it for healthy growth. Pond plants derive their nutrients from fish waste, which helps maintain a natural balance in the pond ecosystem. If you have extra plants after dividing them, consider planting them in low, damp spaces in your garden.

Adding and Checking Pond Plants

To maintain a healthy ecosystem, adding new pond plants is important. For fish ponds, it is recommended to cover up to half of the pond’s surface with floating plants. This provides a place for the fish to hide from predators and keeps them cool in the summer heat while also preventing algae growth by blocking sunlight. Regularly checking the pond plants ensures they are healthy and growing well.

Spring is also a good time to add more plants to your pond. Plants not only add beauty and colour to your pond, but they also help to filter the water and provide oxygen for the fish. Adding more plants, especially floating plants, can also provide shade and shelter for the fish, which can help keep them healthy and happy. Make sure to choose plants that are suited for your climate and the size of your pond.


Checking Pond Liner

If your pond is lined with a pond liner, it is important to check that the edging material covers the pond liner adequately to prevent possible damage from claws or UV rays. Rubber pond liners are UV stable and can withstand prolonged UV exposure. However, a bare edging exposing a pond liner can detract from the pond’s beauty. Planting low, damp plants along the pond’s edge can prevent this.

Start Feeding Your Fish

Spring is a great time to start feeding your fish again after a long winter. Start with small amounts initially, but gradually increase the amount as the fish become accustomed to it. A good rule of thumb is to feed enough that will be consumed within five minutes. Overfeeding can lead to excessive waste and cause problems such as algae growth and poor water quality. Feeding the fish a balanced diet that includes both dry and live foods can help keep them healthy.

Check for Leaks in Water Features

Spring is the perfect time to check your pond’s water features, such as fountains or waterfalls, for any leaks. Leaks can cause the water level to drop and may damage the pump or other equipment. Check the water level daily to see if there are any changes. If you suspect a leak, turn off the pump and check the plumbing and connections for any damage. Repair any leaks as soon as possible to prevent further damage.

Remove Algae

Spring is also a good time to remove any excess algae from your pond. Algae can take over your pond and cause poor water quality. You can remove algae manually using a net or rake or by using an algaecide. It’s important to follow the instructions carefully and not over-treat the pond, as this can lead to more problems.

Add Beneficial Bacteria Treatments

Spring is a great time to add beneficial bacteria treatments to your pond. Beneficial bacteria help to break down organic matter and fish waste, reducing the amount of ammonia and other harmful compounds in the water. This can help keep your pond clean and clear, and your fish healthy. Follow the instructions carefully when adding the bacteria, and make sure to add them on a regular basis for best results.


  • Spring is the perfect time to prepare your pond for the upcoming season. To ensure your pond is healthy and your fish thrive, there are several tasks you should perform.
  • First, remove any de-icer and heaters from the pond. The warmer weather means they are no longer necessary.
  • Next, set up and switch on your pond pump and filter to begin circulating the water. This helps maintain water quality by removing debris and contaminants.
  • Perform a 20% water change to remove any accumulated waste and replenish essential minerals.
  • Turn on waterfalls and fountains to increase oxygen levels in the water, which is important for fish and other aquatic life.
  • Add pond salt to maintain .3-.4% salinity, which can help prevent parasitic infestations.
  • As the temperatures warm, debris and leaves can decay more quickly and negatively impact water quality. Therefore, remove any debris and leaves from your pond.
  • Monitor water parameters regularly to ensure they are within the correct range for your fish and other aquatic life.
  • Algae blooms are common in the spring, but installing a UV clarifier can help combat this issue. Be on the lookout for signs of illness, as the immune systems of your koi are more vulnerable in early spring. By following these steps, you can ensure your pond is healthy and beautiful all season long.
  • Next up, what do to your pond in autumn!


Last Modified: April 6, 2023