Distilled water is free of contaminants, making it one of the best to use on plants. The drawback is that distilled water is costly, especially if you have many plants. It is also not always available, requiring you to consider other water sources.
Alternatives to distilled water for plants include:
- Reverse osmosis water
- Bottled purified water
- Cooled boiled water
- Dehumidifier water
- Aquarium water
- Boiled cooking water
- Banana peel water
- Bottled spring water
- Sparkling water
- Well water
- Melted snow
- Tap water
In this article, I’ll discuss the alternatives to distilled water in detail. I’ll also highlight the precautions when using other water options.
Rainwater is the best for plants because it is soft, oxidized, and nutrient-rich. The impact of rainwater is usually evident within a short time because the foliage is greener and the plants appear healthier. The primary reason for this is the high dissolved oxygen levels, which boosts root mass.
Apart from rainwater, distilled water is the other source with high levels of dissolved oxygen. That’s why these two water sources are the best for plants and are easily swapped for optimal plant growth.
The challenge with rainwater is it is only available during specific seasons. You also need to collect the water, which can be difficult if you live in an apartment or have a flat roof with no gutters.
The quality of rainwater also drops over time. However, if you store it in a sealed rain barrel, away from light, you can use it for some time.
Bird droppings or other waste from the roof and gutters may also make it into the barrel, contaminating the water. In that case, you can use the water only when watering non-edible plants, such as ornamentals or houseplants.
Alternatively, you can collect rainwater as it falls directly from the sky. It may take some time to fill the barrel, but there’s little risk of contamination. You can also safely store this water for longer.
2. Reverse Osmosis Water
Reverse osmosis (RO) water is another great option for your houseplants. The advantage is RO water is so pure because it is free of all ionized minerals. It is also free of chemicals, such as fluoride and chlorine.
Like distilled water, when you use RO water, your plants are safe from toxicity, which slows growth.
The downside is RO water is too pure. It is great because the soil and bacteria remain unaffected when you water your plants. However, it lacks minerals and nutrients essential for plant growth.
So, even if your plants initially appear to be thriving, they will eventually slow down because the RO water doesn’t add value to the soil. Like with distilled water, you will need to alternate with mineral and nutrient-rich alternatives, like rainwater or tap water.
Just ensure your plants are receiving sufficient nutrients from high-quality plant food. An added benefit is that RO water will flush out the salts left behind by tap water or fertilizers, reducing the risks of plant damage.
3. Bottled Purified Water
Purified water is very similar to distilled water. If anything, distilled water is a form of purified water because it is stripped of minerals and impurities. However, bottled purified water contains minerals of less than 10 parts per million (10 mg/l).
Distilled water hardly has any minerals. If it does, it is not more than one ppm (1 mg/l).
So, bottled purified as a good alternative to distilled water because it has similar benefits. The limited minerals are a plus because plants will utilize them without the risk of salt build-up in the soil.
4. Cooled Boiled Water
Tap water is not the best for plants because it contains minerals, heavy metals, and chemicals (chlorine and chloramine). The chemicals can kill soil microbes (including beneficial ones), while the minerals can cause salt buildup over time.
Despite its effect on plants, some people turn to tap water because it is the cheapest and most accessible option. Instead of using the water as it is and risking plant damage, you should consider using cooled boiled water.
When you boil tap, germs, bacteria, and viruses will be eliminated. This water is also free of chlorine and other chemicals used in tap water treatment. The absence of these contaminants makes cooled boiled water safer for plants.
However, it’s worth noting that boiling doesn’t eliminate chloramines. So if your municipal water treatment facility uses chloramine, it’s best to use other water sources for plants, especially in hydroponics and aquaponics.
Chlorine and chloramine won’t cause immediate damage to your garden plants with a single application. However, some sensitive plants like the Venus flytrap and African violets are likely to show signs of stress more quickly after receiving tap water.
The other benefit of cooled boiled water is the pH can become slightly acidic as the mineral salts settle at the bottom.
Wait until the boiled water cools down to 62-72 °F (17-22 °C) before using it on your plants. The temperature helps to prevent shock in plants, especially when other alternatives, such as rainwater, are too cold to use.
The downside is cooled boiled water requires advanced preparation because you need to give boiled water sufficient time to cool.
Plants that are sensitive to tap water, like Calatheas, might still be affected by cooled boiled water because boiling doesn’t affect mineral concentration in the tap water. This is especially true in regions where the tap water system is compromised.
5. Dehumidifier Water
You don’t have to dispose of the water in your dehumidifier reservoir. You can use this water on your plants. Dehumidifier water is soft water but is regarded as “grey water” because it is used water that should ideally go down the drain.
However, you don’t need to waste it if it is clean. You can use it on your plants. Since it is soft water, it has elevated levels of dissolved oxygen, which is great for the roots and optimal plant growth.
You can ensure you get clean water by keeping your home dust-free and the coils in the humidifier cleaner.
One of the challenges of dehumidifier water is some of the water droplets in the air may contain fungi spores. If you use this water on plants with root rot, it may make the situation worse.
6. Aquarium Water
If you have a freshwater fish tank, you can collect and use its water on your plants instead of discarding it. Not only will you be getting good water for your plants, but you will also be fertilizing them. It also doesn’t hurt that you are recycling the water.
Aquarium water is great for plants, but you shouldn’t rely on it exclusively as a source of fertilizer. Sometimes the water has sufficient organic fertilizer for the plants, but if you refresh the water quickly, the nutrients may not be sufficient for your plants.
However, there are instances when aquarium water is not ideal for houseplants.
Avoid using aquarium water when:
- You have used chemicals to control the water’s pH.
- The water is too dirty, possibly because you haven’t changed it for a long time. Although dirty water signifies higher nitrogen levels, the concentration can be problematic for your plants.
- The aquarium has salty water.
Aquarium water has its benefits and drawbacks. You still have to create a balance when using it for your plants, especially if you recently fertilized your houseplants.
7. Boiled Cooking Water
The other little-known yet effective water to use on your plants is boiled cooking water. Most of us drain leftover cooking water used to boil pasta, potatoes, vegetables, eggs, corn, rice, or tea. However, important nutrients and vitamins from the food remain in the water.
Nitrogen, phosphorus, and calcium are some of the nutrients washed from the plants into the water.
For example, vegetable water contains nitrogen, oxygen, iron, and calcium. These nutrients will help plants grow more foliage and manufacture plant cells. The iron will help keep the leaves green and shiny.
Water from boiled potatoes contains phosphorus and minerals. This water will encourage bacterial growth in the soil. It will also stimulate overall plant growth and keep pests from the plants.
The nutrient levels in boiled cooking water are low, so you can fertilize your houseplants every time you water them. You only need to ensure you don’t overwater your plants in a bid to add as much fertilizer as possible.
The boiled cooking water should be cooled before use. You also shouldn’t add salt before collecting the water for your plants.
8. Banana Peel Water
Bananas are rich in magnesium, phosphorus, and calcium. Instead of disposing of the peels, you can soak or boil the peels to extract most of the nutrients and then water your plants. The nutrient level in the water is low, so it is safe to use this water on your plants regularly.
To prepare banana peel water;
- Cut the banana peels into 1-inch (2.5 cm) squares and put them in a bowl of water.
- Allow the setup to sit for 2-3 days. Stir it occasionally.
- Boil the peels for half an hour.
- Strain the water, and discard the peels.
- Allow the liquid to cool before adding an equal amount of fresh water.
- Water your plants.
Soaking will help soften the banana peels and the nutrients will leach out. Some people use the water as it is without boiling, which is also fine. However, boiling gets through the tougher fibers, extracting more nutrients.
Since the boiled banana peel water is rich in nutrients, diluting will allow you to water and fertilize more plants.
9. Bottled Spring Water
If you go to the store and fail to get distilled water for your plants, you can use bottled spring water. It is free from common contaminants like lead, bacteria, and chlorine. However, it has minerals, including calcium and magnesium, which are retained when the water is bottled.
So, as an alternative to distilled water, bottled spring water is great. However, it may be just as costly, so if the reason you want to try a different water source is cost, it may not be the ideal solution.
Another challenge of using bottled spring water is its high mineral and sodium levels. If you use it to water potted plants regularly, it will increase soil salinity and hinder plant growth.
Undoubtedly, bottled spring water is a great alternative. However, you have to use it sparingly. It is best interchanged with RO or distilled water because it will introduce beneficial minerals into the soil.
10. Sparkling Water
Although not cost-effective, sparkling water adds macronutrients into the soil, stimulating plant growth. The carbon dioxide in sparkling water also boosts nitrogen levels in the soil.
Some studies show that when you use carbon dioxide-infused water on your plants, they grow faster. Plants absorb the minerals in sparkling water quickly, resulting in faster leaf growth and a general improvement in plant health.
However, this sudden change in your houseplants’ appearance can be deceptive. Since the plants absorb the nutrients quickly, the soil is just as quickly left bare.
Over time, the plants become weaker. Additionally, plants become dependent on carbonated water for sustenance.
You can opt for sparkling water occasionally to give plants the nutrients they miss when you use distilled water.
11. Well Water
The other water source you can use for your plants is well water. It is free of chlorine and other chemicals that are harmful to plants. However, the mineral concentration in well water is high, although it varies from place to place.
The suitability of the water for your plants will depend on the mineral concentration.
You can test the mineral content in well water using test strips or digital meters. You shouldn’t use it on your plants if it contains too much salt.
Fortunately, you can set up filters, preferably RO filters, to make the water safer for your plants.
12. Melted Snow
Melted snow is almost as good as rainwater. As it falls, it collects nutrients, such as nitric oxide, a great fertilizer for plants. It stimulates healthy root growth and boosts plant resistance to diseases.
When collecting snow for your plants, avoid areas where it may have come into contact with contaminants. For example, snow close to the driveway or public road may contain some salt.
The downside is snow melts slowly. So, you need to give it a few days before it is ready for use.
You also need to ensure the water is not too cold because it will shock the plants, resulting in stunted growth. The ideal water temperature for plants is between 62 and 72 °F (17 and 22 °C).
You can collect snow in a rain barrel, seal it and use it over an extended period. When stored correctly, melted snow will serve you for a long time, and your plants will thrive.
13. Tap Water
Tap water should be one of the last alternatives to distilled water because they are so far apart. However, if you have no other option, you can use tap water to ensure your plants don’t go without water for too long.
Fortunately, water quality varies from place to place, depending on the mineral levels and the chemicals present. Some houseplants are also not as sensitive to tap water, so you may get away with using it occasionally instead of distilled water.
However, if you have spider plants, dracaenas, or even lilies, you should avoid using tap water because they are sensitive to fluoridated water. Calatheas and prayer plants are extremely sensitive to chlorine.
You can make tap water safer for plants by collecting it and allowing it to sit for at least 24 hours for the chlorine to evaporate. You can also set up filtration systems to remove chloramine, fluoride, and minerals from the water.
This video guides you on how to improve tap water quality for your plants:
You can use several types of water on your plants besides distilled water. Some water sources, like purified and reverse osmosis water, are the closest in quality to distilled water.
Some sources are more beneficial because they are nutrient-rich. Examples include rainwater, aquarium water, melted snow, banana peel water, boiled cooking water, dehumidified water, and in some cases, tap water.
As all water sources have pros and cons, you’ll have to decide what works best for your plants and how to control the negative effects, such as salt buildup in the soil.