Should You Use Boiled Potato Water Good on Plants?

You might have heard about boiled potato water’s use in gardening in forums, websites, and among your friends. Isn’t it interesting? This is probably because potato water is a cheap fertilizer alternative and it is readily available!

Boiled potato water can be used for 1) boosting growth, 2) composting, and 3) giving an organic nutrient source because it is rich in potassium and contains phosphorus, zinc, calcium, and magnesium. These minerals are essential in inducing flowering, enhancing fruiting, and improving plant immunity, making potato water good for vegetables, fruits, and houseplants.

If you are wondering how to make and use potato water in your own garden, the next section will provide it for you. Prepare your notes as this information can maintain the health of your garden plants!

1. Boosts Growth by Providing Minerals

Boiled potato water is a rich source of potassium, calcium, magnesium, zinc, and phosphorus. These nutrients are required for optimal plant growth and development.

To help you digest this information easier, I summarized the effect of each nutrient below on plants.

  • Potassium: Aids in disease resistance, facilitates fruit development
  • Phosphorus: Improves flowering, seed formation, and fruiting of plants
  • Calcium: Enhances quantity of harvest
  • Magnesium: Manages sugar transfer from roots to fruits
  • Zinc: Helps in metabolic activities in the plant such as growth and plant part development

So if you use your boiled potato water on your plants instead of just pouring it down the sink, you’re able to take advantage of all the minerals in it!

Plus, as you can see, almost all kinds of plants can benefit from a little bit of boiled potato watering from time to time.

2. Can Be Placed in Compost

Using boiled potato water can hasten decomposition by allowing the growth of beneficial bacteria and fungi. Simply put, this water can help produce compost which can be further used by plants as a nutrient source.

You can throw excess potato water in your compost to help initiate the growth of bacteria and fungi.

In composting, it is important to throw in organic materials. Why? Because microorganisms love eating them. Thus, spraying or pouring your excess potato water will hasten the reproduction of bacteria and fungi.

Remember, the more workers in decomposition, the better.

Learn more about this in our article on whether mold is bad for your compost.

3. Organic Nutrient Source

As an organic nutrient source, boiled potato water is eco-friendly. Unlike chemical fertilizers, it will not harm the environment. Thus, it is used for commercial all-organic farms.

If you are into organic farming, potato water might be for you!

This is because it uses a natural process of cooking—where the nutrients from the potato itself break down and is transferred to the water.

Now, you might be wondering, what are the advantages of using organic sources of nutrients over chemical fertilizers?

Below are the 3 common benefits of using an organic fertilizer like boiled potato water:

  • Easy to make. Later, I will discuss how to create potato water. I am telling you, you can easily make one!
  • Cheap choice. You can even use the leftover potato water when boiling potatoes for your mashed potato!
  • Eco-friendly. Using organic nutrient sources will not pose any negative risk of salt and mineral accumulation in our environment.

However, the downside of organic sources is their weaker concentration of nutrients. Thus, if your plants are exhibiting extreme signs of nutrient deficiency (e.g. yellowing of leaves), the best option to solve this is to use chemical fertilizers.

In a nutshell, using organic sources is best for supplementing nutrients for plants. Whereas, chemical fertilizers are best to use when solving a nutrient problem such as deficiencies.

What is Boiled Potato Water? How is It Made?

Potato water is made by boiling whole, cut, or peeled potatoes to extract the nutrients found in them. The peel of potatoes can also be used to make boiled potato water for plants.

Now that we’ve got all the benefits of using it out of the way, it is important to also understand exactly what potato water is made of.

From the term itself, potato water is the by-product of boiling potatoes. When we say by-product, it is a leftover from a process.

There are 4 common ways to make your own boiled potato water:

  1. Boil whole potatoes in water (30–45 minutes);
  2. Boil only the potato peels in water (10–20 minutes);
  3. Cut potatoes into pieces and then boil them (10–20 minutes);
  4. Blend potatoes in a blender followed by boiling and sieving (30–45 minutes)

The next steps you need to do is to get your potatoes, transfer the leftover water to another container, let it cool, and use it in your garden.

how to make potato fertilizer | tips to grow plants faster

Using boiled potato water is both easy to do and cheap!

Believe it or not, it is as simple as that!

10 Plants to Feed With Boiled Potato Water

Boiled potato water can be used to supply nutrients to succulents such as cacti, garden plants such as vegetables and fruits, and indoor plants like calathea and pothos.

Some plants that can benefit from the nutrient-rich boiled potato water are:

  1. Anthurium
  2. Beans
  3. Cactus
  4. Calathea
  5. Eggplant
  6. Pepper
  7. Philodendron birkin
  8. Pothos
  9. Strawberry
  10. Tomato

Since the dominant nutrients available in potato water are potassium and phosphorus, using potato water is best for fruiting vegetables and indoor plants.

Learn more about this in our article on 3 nutrients you’ll need.

For the most part, phosphorus can promote flowering thereby enhancing the quality of fruits and vegetables. Tomato, pepper, eggplant, beans, and strawberries are flower and fruit producers, so using potato water will be beneficial for these species.

Additionally, potassium heightens the immunity of the plants and is also needed in the flowering process. Calathea, philodendron birkin, anthurium, pothos, and cactus are prone to leaf diseases. Thus, using potato water will boost the resistance of these indoor plants.

How to Use Potato Water in Plants (3 Simple Ways!)

To use boiled potato water in plants, combine 500 mL of regular water with 100 mL of potato water. This can be applied through top watering, bottom watering, or foliar fertilizer.

How to Use Potato Water in Plants
How to Use Potato Water in Plants

1. Top Watering

When watering, apply potato water from the top of the plants. This allows the leaves to have direct contact with the potato water and absorb the nutrients contained within it.

Top watering is generally ideal for vegetables and herbs. This is because they need a lot of water to support the growth of their plant parts, especially the leaves, flowers, and fruits.

Choose the best watering can in our article on hand-picked watering can for your garden.

2. Bottom Watering

Bottom watering, on the other hand, is more concerned with nourishing the soil. It is the watering of plants through the soil and allowing the plants to absorb the nutrients provided by potato water.

Most indoor plants like bottom watering because they require less water and they can be watered only once a week. Examples of indoor plants which love bottom watering are pothos, spider plants, and calatheas.

3. Misting as Foliar Fertilizer

To use as foliar fertilizer, you can transfer the potato water into a spray bottle and mist your plants with it two to three times a week.

Vegetable plants are the best recipient of foliar potato water. This is because you can spray the potato water directly on the vegetables to nourish them. Examples are eggplants, tomatoes, and peppers.

2 Ways to Store Potato Water

Potato water can be stored in the refrigerator for 24 hours. Alternatively, boiled potato water can also be kept frozen until the time of its use.

2 Ways to Store Potato Water
2 Ways to Store Potato Water

1. Refrigerate for 24 Hours

Potato water can be easily stored by refrigerating it. However, the limitation is that this is only good for 24 hours. Bacterial growth may occur after it has been left unused for a whole day, rendering your boiled potato water useless.

2. Freeze and Use Anytime

The best way to store potato water is to freeze it. When potato water is frozen, the nutrients are also preserved. After that, simply thaw it and use it whenever you need it.

When thawing, you can:

  • Boil the frozen potato water once again on a stove.
  • Heat it in a microwave.
  • Let it melt at room temperature.


Is potato water good for tomato plants?

Yes, potato water is good for tomato plants. Potato water is best applied to tomato plants during their flowering stage. This is because potassium and phosphorus, which are key components of potato water, can in initiating flowers and enhance the fruit quality of tomatoes.

Is boiled vegetable water good for plants?

Boiled vegetable water is another good organic nutrient source for plants. This is because vegetable water, in general, contains nutrients broken down by the boiling process. Since vegetables are a rich source of nutrients and minerals, these can also aid in growing and harvesting healthy and high-quality plants.

Is salted potato water good for plants?

Salted potato water is not recommended for plants, especially if a gardener does bottom watering. This is a precaution in potato water use in gardening because the salt may build up in the soil and cause soil toxicity. When this happens, the uptake of essential plant nutrients will be difficult, causing plants to wilt and eventually die.

Do people mist succulents with potato water?

Succulents cannot be misted with potato water. Even though potato water is a rich source of nutrients, spraying them will more likely lead to moldy succulent leaves and unhealthy roots. Considering this, the best way to water succulents is still watering through their growing medium to allow efficient root absorption.

Summary of Is Boiled Potato Water Good for Plants?

Boiled potato water is an organic way to nourish plants since it contains nutrients such as potassium, phosphorus, calcium, magnesium, and zinc that boost plant growth. It can be placed in compost to allow the growth of decomposing agents such as bacteria and fungi.

Vegetables, fruits, indoor plants, and succulents are the best plants to use potato water on. Top watering, bottom watering, or foliar application can all be used to provide potato water for plants. Furthermore, potato water is best stored in the freezer so that it can be used whenever it is needed after thawing.


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