If you have a pond, you know that routine water changes are necessary–no matter how advanced your filtration system is. During these water changes, you may find yourself with a lot of pond water and nowhere to put it until you look around your garden. But is pond water good for your potted plants?

Pond water is good for plants when its clean because it contains beneficial minerals and nutrients such as nitrates. Pond water is not good if it contains chemicals leached from chemical fertilizers or toxic materials. You need to test the pond water before using it for plants.

While pond water is safe and beneficial for your plants, you can’t always turn around and pour it on them without a second thought.

The water you give your plants needs to fit a certain nutrient profile to ensure that it doesn’t contain any harmful contaminants. Thus, you may need to treat your pond water before watering your plants with it.

Is pond water good for potted plants?

Routine maintenance on your pond will include water changes. These can result in having to take out anywhere between 10-50% of your pond’s total volume, leaving you with gallons of water and nowhere to put it.

Luckily, as long as you have a garden and potted plants, you will always have somewhere to safely pour your pond water.

However, there is no universal ‘right’ or ‘wrong’ answer to giving your plants’ pond water. Every pond produces a different water profile unique to its own ecosystem.

You can use pond water to water your potted plants. It can contain rich nutrients, especially if the pond has a healthy fish population. (think about how the aquaponics systems use fish and plants in the same system to cycle nutrients) – – Shelby DeVore, Founder, Farminence

A pond’s types of nutrients and minerals, along with their compositions, are all a result of multiple factors: the pond’s diversity, biomass, fish food, local wildlife, pond plants, climate, and location.

Despite all the water profile possibilities, pond water is often safe for your plants. However, it remains important to test the water to understand what it contains.

I conducted a poll to ask gardeners whether they use pond water for their plants. As you can see below, a majority of them would use the water if they did have a pond. They would find the water beneficial as it contains lot of nutrients.

Does pond water have nutrients for plants?

Pond water has nutrients for plants because it’s a closed ecosystem where these nutrients accumulate. They are introduced by a combination of fish waste, aging plants, natural microbes and pond additives.

We often refer pond water to as ‘fertile water’ because of its nutrient content. It contains both organic and inorganic elements at different concentrations:

  • Macro-nutrients: We find the following in large quantities in ponds; nitrogen, phosphorus, oxygen, carbon. The following are found in smaller quantities; calcium, potassium, sulfur.
  • Micro-nutrients: The levels of the following vary; iron, cobalt, magnesium, chlorine, vitamins.

Yes. pond water is good for plants. if there are fish in the pond their waste can have nitrogen and micronutrients the plants need. One of the good things about pond water is, just like rainwater, pond water won’t have high levels of chlorine which in that sense makes it superior to tap water for your plants. – Nikita Legall, Gardener, Ah Grow!

Is fish pond water good fertilizer?

Fish pond water is good fertilizer because the fish waste releases nitrogenous compounds with high amounts of ammonia and nitrites.

If these levels are too high, it’s toxic to both your fish and plants, making it important that you monitor and treat the water routinely.

I do consider fish water good for plants as long as you provide the required treatment to keep the ammonia levels within acceptable range.

Is pond water safe for potted vegetables?

Pond water is safe for potted vegetables when you have the water tested for toxic contaminants before use. Using pond water on vegetables or edible plants is riskier than regular plants. 

Suppose the water has been tested and appropriately treated. In that case, there should be no problems with using your pond water to water any potted or non-potted vegetable and other edible plants.

Do you need to treat pond water?

You need to treat pond water because it may contain toxic elements that are harmful to plants and humans. The pond water may contain algae that releases harmful bacteria.


Algae are a big threat when using pond water, with dozens of harmful species.

Bacteria in pond water can choke the roots of your plants, preventing them from getting hydration and causing them to dry up and become brittle. Moreover, the bacteria will grow and spread.

Using untreated algae-infested water becomes a bigger problem when used on vegetable or edible plants. Various microbes can cause several illnesses, causing both you and your plants to get severely sick.

However, some types of algae are essential for your pond’s ecosystem and the plants inside. Thus, there must be a balance of how much pond water you use to avoid the risk of harming the plants inside and out of the water.

You can make algae work for you by using it as fertilizer. Pond algae is good fertilizer material that you can add to your compost pile. Make sure to treat the algae first. Clean it well and dry it out before use. Powder the algae and add it to the compost pile for a boost of nutrients.

Stagnant Water

Most ponds have a filtration system to keep the water from being stagnant because this causes the water to become visibly dirtier much quicker and require more cleaning. This may raise concerns about whether the water is safe for plants.

Watering your plants with stagnant pond water should not cause any harm past the actual water and nutrient profiles–which is the case for any pond water, stagnant or not.

How To Treat Pond Water

Treating pond water for your plants is not as difficult as you may think. It does not require a lot of time or chemicals. In fact, we can do it within an hour.

  1. Filtration System: Installing a filtration system will eliminate toxic contaminants in the water.
  2. Test a sample: To know what nutrients and additives are in your water, you can take a pond water sample to a local lab and have it tested.
  3. Filter the Water: Filter the water before using it on your plants. Filters can remove most contaminants that may harm your plants.
  4. Chlorine Removal: It is unlikely that there will be chlorine in your pond, especially if there are fish in it. However, if you add chlorine to your pond, there is a chlorine removal kit that will clear this chemical’s water.

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