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Using Pond Water on Plants: Everything You Need to Know

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Pond water can be used for the irrigation of plants because of the minerals and nutrients it contains.

Using pond water is good for plants because it contains dissolved minerals and nitrates used for healthy growth. Water from a pond also contains decaying plant material that provides nourishment to microorganisms in the soil. However, pond water should be tested and made safe before irrigating plants.

But before you commit yourself to using pond water, there are some things you should know. 

In this article, we will explain what exactly you need to look for when using pond water for plants and the benefits that come with it.

Is Pond Water Good for Plants?

Using Pond water on plants

Similar to the water in an aquaponics system, pond water contains dissolved minerals and Nitrogen in the form of nitrates. 

Nitrogen is so vital because it is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide.

Dissolved minerals can vary by source and are also used in all cellular reactions in plants which results in larger growth.

There are two types of ponds that people refer to which are natural ponds and artificial ponds. The water quality can differ significantly in both cases depending on the various inputs that feed the ponds.

Natural Pond Water

This type of pond occurs naturally in nature and the water in it can come from multiple sources, both good and bad.

In natural ponds, the inputs can vary meaning that depending on its location the chemical and nutrient composition can change with the source of its makeup water.

These types of pond water can be both beneficial and detrimental to plants when irrigated depending on the contaminants in the water.

Natural pond water should be tested and made safe before it is added to both garden plants and lawns.

Fish Ponds (Koi & Goldfish Ponds)

This type of pond water is said to be very good for plants of many kinds, if not all. But for that to be, something must be done first.

The population comes first. The fish in the pond should be small to keep the pond from becoming overpopulated.

Then, keep a check on your fish’s food consumption and be careful not to overfeed them, because when the fishes are full, they will leave the food in the pond to decompose there, which is not a good thing for the pond.

Furthermore, consider providing them with food that can float on the surface of pond water rather than lying on the bottom.

Try covering half of the pond area with plants during the springs and summers. Remember to keep the balance, as unnecessary plants will create certain complications in the pond water.

The more the plants, the more oxygen they use at night, leaving little to no for aquatic pond life.

Always keep the pond water pump clean. Be sure to clean it every 2 to 3 days to ensure that nothing is blocking or compromising the pond water quality in any way.

Clean the pipelines before it is late. Finally, keep the pond water at less than 70 degrees Fahrenheit in temperature to keep the liquefied oxygen intact. How do you keep it cool? By using plants to cover it from above.

Take care of these things, and your pond water is set to be used for various purposes.

See our posts on using rainwater for plants as well as using well water for plants which give an in-depth explanation of using these alternative sources of natural water for plants.

Using Pond water for plants

What Does Pond Water Contain?

Like all other kinds of water, Pond water is made of certain compounds, gasses, sand, nitrates, and sediments. Tiny and larger stones can also be found in the pond water.

Nutrients are obtained by fish wastes, dying plants, and other sources.

These nutrients are composed of nitrates and some other plant nutrients. The nutrients that are mostly found in the pond are macronutrients, nitrogen (N), along with other micronutrients as well.

The ponds with relatively more fish tend to have more natural nutrients from those fish wastes.

However, these wastes have nitrites and other compounds, which can be harmful to fish and the pond.

To reduce the risk to aquatic life in the pond, thankfully, the Nitrogen Cycle is here to save the day as it turns the nitrates into other chemicals, benefiting the pond.


Is a higher quantity of nitrate present in pond water a problem? Yes, it is. Not only that it severely affects the aquatic life in the pond, but it also causes algae to grow rapidly in the water, making it green if the nitrates are not removed instantly.

Nitrates are created in ponds by the fishes themselves. So if you get rid of the fish, you get rid of nitrates. But you would never do that, right?

You want a solution without throwing the fish out. Well, you have to keep a strict balance of their food. Don’t feed them more than they can take.

Runoff Fertilizer

Runoff fertilizer is not a good sign as it may indicate that there are other inputs from unknown sources adding to the pond water.

Although this makes it dangerous for human consumption, it may be a good thing for plants where fertilizers are concerned.

Fertilizer runoff into lakes and ponds comes from many sources, including lawn care products such as fertilizer and pesticides, farm animal waste, and sewage treatment plants.

It may also come from rivers or streams, where it enters through storm drains or seeps out of landfills.

If the are cases of runoff fertilizers in pond water then there is definitely a possibility of other toxic contaminants in there as well and the water should be checked before it is used on plants.

Other Plant Nutrients:

Other than nitrates, the pond?s water contains some rich nutrients that are beneficial for plants. Due to these rich nutrients, pond water becomes ideal for plant growth. 

Furthermore, this water is used to increase the quality of the soil, not only for the smaller garden areas but also on some prominent fields.

For a long time, pond water has been used for simple irrigation purposes. This water can increase the growth rate of the plants by enriching the soil. Also known as “Natural Fertilizer,? the pond water positively affects the plants if kept in balance.

The Dangers in Using Pond Water on Plants:

Despite the advantages of using pond water for plants, there are some drawbacks to it. Similar to using spring water for plants, the water contains some compounds that might not be good to interact with.


Ammonia is created in the ponds by the breaking of waste by fish and plants. The breaking of ammonia is usually carried out by the Nitrogen Cycle. But if the ammonia level is getting high, this is not good for the pond life inside.


The nitrites are created when the bacteria break down the ammonia during the Nitrogen Cycle. Their presence in the water is a serious matter, as they can tie up the fish’s blood cells, which causes several fatal diseases. If your fish is catching its breath at the surface many times, that can be a sign of nitrites’ high quantity.

Gray Water:

Water that has been used already is called Greywater.

A greywater system uses rainwater from the roof of your home to flush toilets and wash dishes. It works by diverting the flow of water through a pipe into a tank where it sits overnight. In the morning, the water drains out of the tank and flows back down the drainpipe.

Most people make ponds to accumulate greywater to filter and put it to good use. 

Using a pond to accumulate greywater is very cost-effective but it can cause algae blooms from nutrients in the greywater.

Low Oxygen Content Water from Algae:

The growth of algae on the water?s surface stops the sunlight from reaching the plants inside, making it hard to photosynthesize.

Algae are tiny plants and will use sunlight, nutrients, and water to grow just like the larger plants we ar accustomed to.

What this means is that if pond water contains fertilizers from runoff water, the algae population can bloom uncontrollably causing a rapid depletion in oxygen and nutrient levels in the pond water. 

A good sign that there is an algae bloom is that the pond is overrun with algae and is covered by the stuff.

Excessive algae growth will also significantly deplete the oxygen levels causing biological life to stifle and die and is evident in dying fish and other aquatic animals in the pond. 

That is why the algae must be removed at the early stages before any complications occur and the pond water should be checked before use. 


The water that has not been properly maintained and cleaned is where the pathogens find their ideal home. Pathogens are those living things that negatively affect the beings they contact.

Pond Water Treatment Process

There are many ways to treat pond water. Here are some of the most common methods:

1. Filters:

Filtering the pond water is one way to remove impurities. There are different types of filters available. They include sand filters, carbon filters, and ceramic filters.

2. Filtration Systems:

Filtration systems are another way to purify pond water. These systems use various materials to filter out the contaminants.

3. UV Lights:

UV lights are used to kill bacteria and viruses present in the pond water by exposing them to UV light.

4. Chlorination:

Chlorine is added to the pond water to kill harmful microorganisms. It is usually done using chlorine tablets or liquid form.

5. Sediment Removal:

Sediment removal involves removing sediment from the pond water. This process helps to keep the pond clear.

6. Chemical Treatments:

Chemical treatments involve adding chemicals to the pond water to make it safer for humans and animals.

Can Plants be Used to Clean Pond Water?

Water plants can be added to ponds to reduce nutrient buildup and algae blooms. Plants like floating water lilies can also actively filter pond water by trapping tiny sediments and also using dissolved nutrients known to cause algae blooms. 

How to Prevent Algae Blooms?

There are other ways to prevent algae blooms in ponds. The first thing you need to do is get rid of excess nitrogen and phosphorus in the pond.

This can be done by removing the source of these nutrients and can include diverting known runoff water sources that feed the pond.

Another way to prevent algae blooms is to add a chemical called algaecide. These chemicals kill off the algae and keep the pond free of algae. They are usually available in liquid form and come in different concentrations.

Can You Use Pond Water In Aquaponics?

Aquaponic means that fishes and plants will grow simultaneously.

The simple answer is that it depends on what kind of pond the water came from. Some ponds are safe for use in aquaponics, and others are not. Before you can use pond water in your system, you need to know how clean it is.

Generally speaking, ponds that already have fish in them are ideal for the aquaponics system, as plants consume the waste and decay of the fishes for their growth purpose.

Pond water can blend seamlessly into an aquaponic system when added.

The water can also be used in the hydroponics system, as the water is enriched with all the nutrients for plant growth.

Can you Use Pond Water on the Lawn?

Pond water can be used to water lawns because in addition to hydration the pond water will contain dissolved minerals and nitrogen in the form of soluble nitrates.

These minerals are used for the healthy growth and development of lawn grass. The nitrogen from the nitrates is used for the production of lush green blades.

Therefore if the pond water is used to irrigate a lawn then you should expect a greener healthier lawn.

The only downside to using pond water on the lawn is that you may have to mow it a lot more frequently. 

If you want to use the pond water for other purposes such as irrigation, then you may need to get a pump to move the water around and a sprinkler to evenly distribute the water over a large space.

It is a good idea to use pond water for lawns. Go for it!

The Takeaway

Pond water is good for plants because it is full of dissolved minerals and oxygen. If you use pond water to water your plants, you can save yourself a lot of money.

Treating the water by boiling it will kill any bacteria or other microorganisms in the water that could cause disease in the plants or make them taste bad. The boiling process will also remove any dirt or sediment in the water.

The nutrients in pond water aid the growth of most types of plants. Research has shown that when pond water is used to water plants, they grow faster than normal and are more likely to survive.

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