As with any part of the garden, a pond will need regular maintenance to keep plants in check, especially as pond plants can be vigorous growers.


Without a pump and filtration system, you will need the correct balance of plants to keep your water clean and clear. All ponds green up a little when the water warms up but don’t panic – if the balance is right it will quickly clear again. The removal of seedheads will also help reduce weeding and thinning in future.

Avoid conducting maintenance in spring, when you may inadvertently remove tadpoles and other aquatic larvae and eggs from the pond. It's also worth leaving any vegetation you’ve removed next to the pond for a few hours, so any invertebrates hidden amongst it can make their way back to the water. Do check leaves for eggs, and return any you find to the pond.

Discover four tips for summer pond maintenance, below.

Avoid conducting maintenance in spring when you may inadvertently remove tadpoles and other aquatic larvae and eggs from the pond.

Top up the water

Topping up the garden pond.
Topping up a garden pond with a plastic trug of water

Top up water as it evaporates in summer, causing the level to drop. Ideally use rainwater from a butt around once a week or as needed. If you have only tap water available, leave it to rest for 24 hours before adding to the pond, to enable any harmful chemicals such as chlorine, to evaporate.

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Clear decaying vegetation

Clearing vegetation from a pond.
Clearing decaying water lily pads from a pond

Clear decaying vegetation, including old water lily leaves, which can increase nitrogen levels, turning water green while building up a layer of sediment at the bottom, which can make the pond smell. Remove dead or dying foliage frequently.

Remove pond algae

Reducing pond algae
Finding blanketweed in a pond

Remove pond algae, such as blanket weed, which spreads quickly and can choke a pond. Do it by hand or use a bamboo cane, twiddling it around and then taking out the smaller bits with a net. Duckweed can also out-grow its welcome in a pond and should be removed by hand.

Reduce oxygenators

Reducing oxygentors
Removing excess aquatic plants

Reduce the volume of oxygenators, such as this hornwort, when they fill more than one third of the pond. These are essential for ponds and keep the water clean, but they need to be prevented from taking over.


Water forget-me-not
Placing a water forget-me-not in an aquatic pot into a pond

Weed between marginal plants, such as water forget-me-not, as you would between border plants, making sure to take out unwanted seedlings as you go. Sometimes it's easier to remove the pot they're growing in, then divide and replant the marginal before placing it back in the water.

No pond?

Not got a garden pond? Here's how to build your own garden pond.