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Guide

Best Water For Indoor Plants

Dumping a cup of tap water on your plant once a week may be doing more harm than good. Here’s what to know about using different types of water to help your houseplants thrive.

Signs Your Plant Is Unhappy With Its Water

  • Overwatering signs: Signs of overwatering your plants include yellow, or drooping leaves, mushy brown spots, and a musty smell.

  • Underwatering signs: You may be over watering your plants if the leaf tips get brown and crispy. Also, the tips of the leaves could curl, or the leaves could curl into themselves when the plant needs water.

  • Sensitivity to chemicals or contaminants: Some plants are sensitive to tap water. Symptoms include yellowing or brown leaves.

What Is The Healthiest Water For Plants?

There are pros and cons for different kinds of water. Certainly plants need water to survive, but water quality does matter when watering houseplants.

Aquarium Water

If you have fish in your home, you may be surprised to hear that you can water your plants with water from your aquarium rather than throwing it out when you clean the tank. While the dirty water is not healthy for your fish, it has beneficial bacteria (fish poop makes excellent fertilizer, just like using horse and chicken manure in your outdoor garden), potassium, phosphorus, nitrogen, and other trace minerals.

The obvious caveat is not to use water from a saltwater tank.

Fish poop is an excellent natural fertilizer for houseplants.

Distilled Water

Many people water plants with distilled water, which has been put through the distillation process. Distillation is a process where water is condensed and evaporated in order to remove all traces of chemicals, minerals, and heavy metals. Distilled water is free from bacteria and viruses, but also lacks essential nutrients.

Plants watered with distilled water usually need additional fertilizer.

Purified Water

Purified or filtered water is water that has been put through a filtration process to remove impurities. Purified bottled water can be purchased at most grocery stores, but the cost can add up.

Some plant owners use a pitcher water filtration system to filter tap water for a more economical option.

Rain Water

Many people will either put their houseplants outside during a gentle rain or gather rain water for watering their plants. In many cases, this is a safe and effective option, as most rain water does not contain salt, minerals, or treatment additives, like chlorine. Rain water contains micronutrients that support plant growth, and many plant owners say their plants watered with rain water grow faster and are a more vibrant green.

But rain water can sometimes contain pathogens or chemicals from runoff. If the water sits in a rain barrel for too long, bacterial pathogens can also begin to grow. If you notice your plants not thriving with rain water, switch to a different type of water or use a water filter.

Spring Water

Spring water contains natural nutrients that are excellent for plant growth. If you have access to natural spring water, absolutely use that. However, bottled spring water will provide the same nutrients, at a cost. If you only have a couple plants that tend to be sensitive to tap water, it may be worth it to purchase spring water to baby those plants.

Tap Water

Many people do water their houseplants with tap water; however, you should know the quality of your water. Hard water has a high mineral content, which will be mostly comprised of calcium and magnesium carbonates, bicarbonates and sulfites. Just like how hard water can cause limescale to accumulate in your tub and toilet, the calcium and magnesium deposits can gather at the top of the soil. Build up of these minerals is harmful to your plant, and can prevent the plant roots from absorbing water and needed nutrients from the soil.

You can flush the build up every few months with rainwater or distilled water.

Fluoride is in the tap water of most municipalities which can be bad because fluoride can create fluoride toxicity in some plants. Other additives, like chlorine and chloramine, are disinfectants that kill harmful pathogens in the water. Chloramines have been shown to be very damaging to the plant’s roots and can lead to brown tips on the leaves, stunted growth, and root rot.

While some houseplants do fine with tap water, others might be sensitive to the fluoride and other chemicals.

One trick is to let your tap water sit for at least 24 hours prior to using it to water plants. This gives the chlorine time to evaporate which makes it safer for your indoor gardening needs.

Leaving your water sitting out overnight does not alleviate the problem of fluoride in the water; however, not all plants are susceptible to fluoride toxicity. Plants that have long, narrow leaves are most vulnerable to fluoride, including spider plants, peace lilies, and Dracaena.

Softened water is also problematic for houseplants. Most water softeners soften the water with sodium ions. These sodium ions build up in the soil and can lead to sick plants.

Well Water

Although this is also water that comes right from your faucet, well water is untreated ground water. Well water contains natural minerals like calcium and magnesium which your plants need to survive, but you can have too much of a good thing. Sometimes well water can contain excessive nitrates, which can result in over-fertilization. If you live near a ranch or farm, check your water for nitrates. Well water can also contain too much iron, which can cause stunted growth.

Well water can be purified via reverse osmosis or with a water purification kit. Ideally, homeowners test their well water annually to ensure it does not contain bacteria or harmful chemicals that could cause harm to people, pets, or plants.

Water Temperature & Watering Method Matter

Whatever type of water makes your plants happy, it’s important to remember a couple things. Plants do not like extremely hot or cold water. Room temperature water is ideal. If possible, let your watering can sit out on the counter.

Also, some plants do not like wet foliage, yet it’s difficult to get a watering can to soil level. A perfect example is the African violet. Instead of watering these beauties from the top, place the pot in a saucer of water for about 30 minutes. The plant will absorb water through the pot’s drainage holes and up into the root system through a process known as bottom watering.


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