Best Water For Your Plants: Taking Care of Your Home Garden

If you can safely drink tap water at home, then plants can also safely take the water. However, the water that you get in taps contains a lot of chlorine and chloramines which kills all microorganisms, including beneficial microorganisms needed by plants.

Reverse osmosis water is pure water which makes it suitable not only for plants but also for human consumption – this makes it the best water for plants.

Best Water for Plants: Reverse Osmosis

Plants take in water through osmosis. It is easier for plants uptake water to get into the roots through osmosis when the water is pure. Afterwards, you can supplement the plants for the minerals they lack when they take in pure RO water. Read on to learn more on the best water for growing plants:

Why Reverse Osmosis is the Best Water for Growing Plants

Just like contaminated water is not safe for human consumption, it is not safe for plants as well. Most of the contaminants found in water from different sources are harmful to plants. Even worse, plants might absorb toxins that might be passed along to humans through ingestion.

Besides the toxins being passed to humans, they may manifest in plants in different ways including deformities, slow or stunted growth, displeasing looks in plants, and burnt leaf margins due to buildup of salts. In severe cases, contaminants can lead to plant death.

When there are so many solids in irrigation water, the water might injure the roots of plants, which is why the best water for indoor plants is RO water which has no dissolved solids. When plant roots are damaged, the water and nutrient uptake is severed. Again, water-borne bacteria might cause plant roots to rot by causing fungal infection. If you are wondering – what is the best water for plants? – then you can try out RO water.

In soilless media or soil culture, inert materials can act as a buffer and can also facilitate collection of some contaminants that RO helps to reduce. In systems such as hydroponics where water is in direct contact with the roots, contaminants are easily absorbed. As such, farmers consider RO water as the best water for indoor plants. Unless the water is tested and the level of contaminants is said to be low, hydroponics have to use RO water.

If you want to control how much nutrients go into your plants, you can use RO water. When considering what type of water is best for plants, you can irrigate your plants with RO water, which is pure, and then accurately measure the nutrients to give to plants. This way, you do not have to guess the ions that are already in water – this way, you can reduce nutrient toxicity.  To learn about other reverse osmosis benefits, click here.

How Does Reverse Osmosis Work?

Reverse osmosis water is water filtered of all impurities and foreign particles to leave pure water. Before water goes through the reverse osmosis system, it goes through a sediment filter that removes large particles. It is then passed through a semipermeable membrane that removes minute particles, including dissolved substances, pesticides, metals, micro-organisms, and random particles. The only things that RO systems do not remove are dissolved gases which makes RO water the best water for plants.

Reverse osmosis systems are classified as either hollow fiber or spiral wound. Both systems are designed to increase osmotic pressure to facilitate reverse osmosis. Hollow fiber membranes sport a large surface area, but they clog more than spiral wound membranes. The hollow fiber membranes are easier to maintain. If you live in an area where water has a lot of dissolved solids, spiral wound membranes are the best.

Besides the two types of membranes, different membranes are designed to filter out particles of various sizes. Some membranes can trap particles as small as 0.0001 microns while others can only trap particles as small as 0.1 microns. The membrane that traps as many impurities as possible produces the best water for growing plants. If you have a large area to water, the size of an RO system you choose should be big enough to produce a large amount of water.

RO water membranes are also classified based on recovery state – this refers to the volume of treated water produced compared to the amount of untreated water introduced into the RO system. The recovery state is calculated by dividing the quantity of expelled water by the volume of water entering the RO system. The effectiveness of most household systems ranges from 20 to 30 per cent – with the rest of the water (called reject water) being used for flushing out the water with impurities.

You also need to consider the maintenance of RO systems and their membranes. Membranes get worn out and require replacement after about five years. Some membranes require replacement after one or two years.

After passing the water through the semipermeable membrane, it is then passed through a carbon or charcoal filter that removes unwanted smells. After filtration, the water is now ready for plant use. The whole process makes reverse osmosis water the best water for plants.

Best Water for Plants: What NOT to Use

Sometimes tap water is acidic and poisonous and unless the water has been tested and found healthy for plants, you should avoid it. When water goes through the RO system, everything in water is removed including magnesium and calcium which naturally occur in water. While these nutrients are needed in moderate amounts, they are still essential for plants. Calcium and magnesium are needed in higher amounts than micronutrients and lower amounts than macronutrients.

As a grower, you need to understand that RO-treated water is corrosive. Calcium and magnesium act as buffers against corrosion in metallic pipes. When water hardness is removed, RO-treated water will eat away galvanized or copper pipes. There are many best plants for water beads, but you can only water the plants if the pipes are not corroded. Ensure that the pipes in your irrigation system can withstand pure water.


What type of water is best for plants? RO water works perfectly for most plants especially in hydroponics. If you are still wondering what is the best water for plants, you should try RO water for your plants. The best plants for water beads can use purified water.