Reverse Osmosis: Does it really help your hydroponic grow room?
Reverse Osmosis: Does it really help your hydroponic grow room?

Reverse Osmosis: Does it Really Help Your Hydroponic Grow Room

Illustration of how reverse osmosis works

Those who have experience with growing plants, be it large production or small gardens, know that it takes a specific kind of care and attention to foster healthy yields. Even with well-known methods like hydroponics, growers are still perfecting the techniques.

When it comes to hydroponics, you need to use top-quality water to nourish your plants. Hydroponic gardening relies entirely on water as the source of the plants’ uptake of nutrients and oxygen. Water filtered through reverse osmosis is considered a preferred method...but is it truly the best way to go?

What is Osmosis?

Before understanding the process of reverse osmosis, it is necessary to understand how osmosis works.

Osmosis is the passage of a solvent through a membrane and to a higher-concentrated solution. This levels out the playing field, as the two solutions result in an equal net concentration.

This process was taken and restructured. From it developed reverse osmosis: a way to get rid of harmful molecules in water.

Illustration of how reverse osmosis works

Reverse Osmosis

Reverse osmosis (RO) tampers with the natural flow of the solution. It involves an external force shifting a higher concentrated solution through a membrane to a lower concentration. This external force is pressure.

When it comes to a reverse osmosis filtration system, water is pushed through a semipermeable membrane that does not allow any particles larger than about 1 micron pass. To put things in perspective, a human hair is about 50-75 microns. This barrier will not let much get by!

Indeed, reverse osmosis will get rid of silt, sediment, iron, calcium, magnesium, chloramine, mercury, lead, etc. These are some of the contaminants that, if consumed in high amounts, can harm a living thing—whether it be a human or a plant.

RO for Plant Growth 

Plants growing in a tank

Plant growers have had a long debate over what kind of water is best to grow plants with. Hard water, soft water, RO filtered water?

Hard water is not altogether a bad option; the high concentration of the nutrients calcium and magnesium can help the plants to a certain extent. However, you cannot overdo the dosage and you must be weary of the high alkalinity of hard water. A high pH can cause a build-up of nutrients like molybdenum, which can be poisonous to plants.

Soft water, on the other hand, can carry too much sodium. This will stunt their growth.

Water filtered through reverse osmosis (RO) provides a baseline solution; no contaminants are in the water to begin with. You can now be sure that each batch of water you use is the same—no need to test for what kind of molecules are present and might affect your plants!

RO for Hydroponics

Illustration of hydroponic system

Hydroponics is a method of growing plants in a bath of a nutrient-rich, water based solution. This allows the roots to be in direct contact with both adequate amounts of nutrients and oxygen.

Growing with soil often gives way to less pest-control and more water intake. A water reservoir used in hydroponics oxygenates the water and constantly recycles the unused water at the end of the process. According to Green Our Planet, hydroponics offers “Up to 90% more efficient use of water” than soil-based production; the ability to garden indoors offers more space and new places to start a grow room.

So why count on reverse osmosis? Feeding your plants the right balance of nutrients should be your top priority when you turn to hydroponics. Therefore, RO filtered water that is free from contaminants at the start allows growers to control the nutrients they are adding, as well as the pH of the solution.

What nutrients are needed?

Various nutrients

Like we mentioned, reverse osmosis gives you a clean slate of water to work with. However, without any nutrients in it your plants won’t grow. Make sure you’re giving your plants these size essential nutrients for plant growth:

  • Nitrogen is an essential component of chlorophyll and helps plants grow green.
  • Potassium is needed for enzyme production and strong stem growth.
  • Magnesium is also an essential component of chlorophyll.
  • Sulfur produces protein and enzymes needed for chlorophyll formation.
  • Calcium is for cell wall formation.
  • Phosphorus helps to fight disease and form roots.

Just like humans, each plant is unique and may require a different ratio of ingredients to maintain proper health. Be sure to add in the correct amount of nutrition to your feeding solutions for the best possible growth.

Buying an RO system

A reverse osmosis system is easy to find and purchase. Some even have 5-Stage Filters that really fine-tune filtration and guarantee quality results. Although they can be a bit expensive and may require some upkeep—like changing the carbon prefilter or membrane—the rewards outweigh the risks.

If you want to grow plants with the confidence start with the cleanest slate possible: reverse osmosis water . This is why a reverse osmosis water filter just might be the best solution to help your hydroponic grow room!


NU Aqua

NU Aqua

@Roy: The RODI system can go for 75 gallons of water per day. That’s approximately, 3.125 gal/hr. It is however, important to note that the incoming water pressure may affect the time to fill your reservoir.



My nutrients say that I should use R/O water to mix up the tea. How can I get 50 gallons from the R/O system at one time. And how long will it take?

NU Aqua

NU Aqua

@Edward: It is definitely worth it! The pH level remains relatively stable when transitioning from tap water to RO water, mainly requiring adjustments to the schedule. These intervals are not as burdensome as they may seem. RO water offers greater stability compared to tap water, especially when utilizing an RODI system. In contrast, using tap water, particularly when it’s rich in minerals and salts, necessitates additional adjustments to the nutrient content of the water.



I know that RO water is preferred but there seems to be a lot of work keeping the ph right . Is it really worth the effort ?

Leave a comment

All comments are moderated before being published