What is the best water for plants? Whether you're growing decorative houseplants indoors, tropical plants, beautiful flowers outside, or have a large food plot full of vegetables and fruits, you have probably found conflicting information online. But the kind of water you use does matter to the health of your plants and to make plants grow their best and strongest. Let's deep dive into the best water for plants to make the best decision.
We are in a hard water area and use rainwater collection and well water for our gardens and indoor plants alike (which is full of natural minerals), but you may not have that option. Or you may have specific build up in the soil and you need to avoid certain minerals. Type of water matters another are different types of water.
Clean rainwater or spring water is the best option for watering your plants, but what if you don't have that option?
How is your local tap water quality?
While many people have ample access to tap water, it isn’t always the most beneficial option to water plants.
Water can be classified as ‘hard’ or ‘soft’, with hard water containing more minerals than soft water.
Tap water is generally hard, and while most plants can survive on hard water, sensitive plants like Calatheas (also known as prayer plants) will quickly die from the harsh excessive minerals.
Look for brown spots and other tell tale signs on your plants.
Another concern with tap water is that many areas’ water contains chlorine and fluoride, which can be harmful to plants. Tap water can also contain high levels of sodium, which can collect in the soil at amounts toxic to some plants.
Lastly, if there are high levels of magnesium or calcium in the tap water, it may build up and create a hydrophobic layer in the soil. This layer can cause drainage issues, either preventing moisture and oxygen from reaching the roots of your plant or causing it to pool around the roots and cause rot and fungal growth.
If you decide to water your plants with tap water, it’s recommended to let the tap water sit in a container overnight so that the chlorine will dissipate. Also, it’s worth researching your local tap water and the type and amount of minerals that it may contain.
Rain or Snow Water
Rain and snow water is considered good for plants and one of the superior watering choices for plants by many. It’s what plants would receive in their natural habitat, and is usually clean and free of harmful metals.
In many places, however, rainwater can be polluted and acidic, causing harm to plants. It’s worth considering your local area’s level of pollution and smog.
Do you have harmful chemicals in your water? Can you get it tested. It is a good idea if you can.
If your area has clean rainwater, the lucky part is that it’s very easy to procure. A rain barrel is easy to setup and use.
We have them around our property and next to our animals and annual garden with plans for even more.
Do you have a filtration system or water filter?
Filtered water can be an excellent choice for your plants. Using a charcoal filter, such as faucet-applied filters or filtered pitchers, can remove additives such as chlorine, fluoride, and heavy metals from water.
The only caveat is that filters can be expensive. If you decide to use filtered water, it’s still recommended to let it sit overnight and allow any chlorine to dissipate.
Softened water can be extremely harmful to plants. Water softeners work by removing calcium and magnesium ions and replacing them with sodium ions, which will throw off the water balance of your plants and hinder their growth.
In every case, it’s better to use tap water that hasn’t been passed through a water softener. Otherwise, you’re almost guaranteed to slowly kill your plants through sodium toxicity.
Bottled water can be a great alternative to tap water. It’s free of contaminants and doesn’t contain any other concerns.
It’s expensive, however, especially when considering that tap water that has been allowed to sit overnight is essentially the same thing.
Also, the waste associated with using bottled water can be a major drawback, especially if one of your focuses is keeping an eco-friendly garden.
It’s recommended that you use high-quality or filtered tap water instead of bottled water.
Do you have a fish tank?
A great way to make the best of your aquarium water changes is using the water in your garden.
This water has many of the same nutrients as fertilizer, including potassium, nitrogen, phosphorus, and beneficial bacteria. It is already purified of harmful additives and reduces the water waste in your household.
It’s important to note that you can only use freshwater aquarium water. Saltwater will quickly result in sodium toxicity and kill your plants. If you have a freshwater aquarium, however, this is a great option.
Distilled water is made by boiling water and collecting the steam. This process removes all contaminants and makes the water completely safe for plants - but it also removes all of the beneficial minerals.
These minerals in other types of water are extremely beneficial to plant growth, and using distilled water can thus result in stunting.
If you have sensitive plants, distilled water can be a great option. Otherwise, it’s worth looking into cheaper and easier-to-access options like filtered water which will give your plants added minerals.
Spring water is harvested from natural springs, and doesn’t contain additives like chlorine or fluoride. Also, it doesn’t contain elements or metals that can harm your plants.
Spring water is extremely beneficial to plants, and can be either taken directly from the spring or purchased as bottled spring water.
As with other bottled waters, there are still concerns about cost and ecological impact when using spring water. It’s generally more difficult to access unless you live near a spring.
Rainwater and tap water may be better choices for most gardeners.
Purified water is similar to distilled water since almost everything is removed from the water. In the case of purified water, everything except water is removed.
Purified water is beneficial for sensitive plants, but isn’t necessary and may 9cause detriment to most other plants.
Purified water can be purchased in most chain retailers, and is a decent option if the tap water or rainwater locally is polluted or toxic.
Many plants will thrive better on the minerals and nutrients contained in aquarium water, rainwater, and filtered tap water, however.
R/O (Reverse Osmosis) Water
Reverse osmosis is a technique of filtration that is used to remove minerals and impurities from water.
These minerals and impurities often include chloramine, salts, and heavy metals. Since impurities in the water can interfere with fertilizers, many people prefer to use reverse osmosis water for their plants.
Since reverse osmosis water lacks necessary nutrients and minerals, it is integral that you use a well-balanced fertilizer. Many stores carry reverse osmosis water, but like bottled water, it may prove costly and ecologically harmful.
You can also install a reverse osmosis filter in your home, but the filters are very expensive.
R/O (Reverse Osmosis) Waste
Reverse osmosis waste is water containing all of the contaminants separated from the clean water produced. It isn’t suitable for human consumption, since it contains all harmful minerals and chemicals removed, including salt, heavy metals, and chloramine.
Reverse osmosis waste isn’t suitable for plants either, since the chemicals and metals concentrated in it will quickly result in toxicity and kill your plants. There are beneficial minerals contained in reverse osmosis waste, but they’re concentrated to such a degree that they’re guaranteed to only cause harm.
Hard water is water with high mineral content. In terms of plant health, it’s advised to avoid particularly hard water. It isn’t as detrimental to your plants as things like saltwater and reverse osmosis waste, but can build up and cause harm if the right precautions aren’t taken.
It’s important to flush the topsoil on occasion using distilled water to prevent the buildup of minerals on the soil’s surface. When there is a high mineral content in water, it will dehydrate plants and can cause wilting and stunting. Washing out the soil will reduce the likelihood of these problems occurring.
If you decide to use hard water, it is important to monitor your plants and use cleaner water if you notice signs of wilting or stunting.
The Best Water For Plants
There’s no one correct answer regarding the best water for houseplants, but there’s certainly a best choice of water for every particular situation.
Depending on your local resources and their cleanliness, rainwater and filtered tap water are great options for plants. They’re generally clean and accessible, but it’s important to check that the pollution and minerals locally aren’t at levels where they would harm your plants.
If you keep a freshwater aquarium, there’s no better option for watering your plants than the excess produced from water changes. And if your local water is unclean, there are many great options like purified water on the market that are worth considering.
Regardless of what water you use, it’s important to watch your plant for signs like wilting and drooping. This is your plant telling you that something is wrong, and addressing it early to adjust your care will keep your plants vibrant and growing.
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