Stainless Steel Pipes in Hydroponics: Should You Use Them?

Hydroponic systems, specifically nutrient film technique (NFT) types, are usually made of polyvinyl chloride (PVC) pipes which are plastic. But is it possible to use stainless steel pipes for hydroponic systems instead? Let us find out the answer today!

Generally, stainless steel pipes are not used in hydroponics due to possibilities of galvanic corrosion, heaviness, and high initial costs. However, some gardeners still use them to take advantage of their durability, resistance to rusting, and cleanliness.

Will stainless steel pipes allow for easy transport of the hydroponic system in cases of garden rearrangement? Is it better to invest in stainless steel pipes considering the prices of raw materials and labor? If you also have these questions, continue reading and let me help you decide.

3 Reasons Why You Should Not Use Stainless Steel Pipes

Stainless steel pipes are not recommended in hydroponics due to their disadvantages such as 1) risk of galvanic corrosion, 2) impractical heaviness, and 3) high initial cost.

1. Risk of Galvanic Corrosion

Aluminum causes galvanic corrosion in stainless steel pipes used for building hydroponic systems.

For you to be more familiar with galvanic corrosion, here’s a quick explanation.

Galvanic corrosion happens when another element, in significant amounts, comes in contact with a specific metal. For example, a copper pipe can deteriorate when it meets a steel pipe in a water junction.

The fact that we are adding various nutrients and elements to the hydroponic water makes hydroponic systems built with stainless steel pipes prone to galvanic corrosion.

2. Impractical Heaviness

Using stainless steel pipes is not practical in temporary gardens because it will be difficult to transfer the entire hydroponic system due to its heaviness.

If you are someone who is a fan of frequently rearranging the components of your garden, like me, a stainless steel hydroponic system might not be the best for you.

Imagine having to carry all of those heavy pipes around! It is not just ideal.

3. High Initial Cost

Raw stainless steel pipes cost way higher than a complete set of nutrient film technique hydroponics with add-ons. Another possible additional cost would be the welding expenses, plus labor. This makes it impractical for beginners and regular hobbyists in hydroponic gardening.

In reality, a complete set for a nutrient film technique hydroponic system like the one below is available on Amazon. This could be yours by just using your fingertips!

Honestly, emerging cheap hydroponic sets makes it less and less practical to create your own, especially if you are going to use stainless steel pipes.

Another possible cost of using stainless steel pipes is welding costs—including welding tools and labor. This could add up so much for the initial cost unless you have your own welding machine.

So from a practical point of view, the only factor that can beat these aforementioned pros is convenience. The convenience that you can find in pre-built hydroponic systems.

Why Some Use Stainless Steel Pipes in Hydroponics

Stainless steel pipes are sometimes used in nutrient film technique (NFT) hydroponics due to their inherently beneficial properties. More specifically, they are used for their: 1) durability, 2) resistance to rusting, and 3) ease of cleaning.

Before moving forward, let us know what hydroponic system usually involves the usage of pipes. Let me introduce you to the nutrient film technique (NFT) hydroponics.

In the nutrient film technique, water is delivered to pipes using a pump that circulates the hydroponic solution throughout the system.

In each pipe, there are holes that house the hydroponic vegetables and herbs. In each hole, a net pot filled with growing medium holds your plant while the roots dangle towards the nutrient water. To keep plants growing, the system recirculates water from and to a reservoir.

As you can see from the illustration above, pipes play an important role in nutrient film technique hydroponics. Thus, choosing the best material for it is a critical step.

1. Durability

Aside from lasting for so many years, stainless steel pipes can resist oxidation and they perform well even in high temperatures! These properties are caused by the composition of stainless steel pipes. We will jump on that later!

2. Resistance to Rust

Coming in from another angle, stainless steel pipes are not prone to rust. This is greatly advantageous for hydroponic systems, which generally require a generous amount of water.

3. Ease of Cleaning

Stainless steel pipes are easier to clean. For dirt and plant or soil debris, you can just use a dry cloth to remove these potential contaminants.

Although sanitation using food-grade hydrogen peroxide or bleach is still advised, new models of stainless steel pipes with a polymer coating to prevent bacterial growth are being studied.

Composition of Stainless Steel Pipes

Generally, stainless steel products are composed of primarily iron and at least 11.5% of chromium. Elements such as nickel, titanium, and niobium can also be supplemented for increased toughness and to inhibit further deterioration.

This may sound a little too scientific, but these elements are necessary to increase the durability of steel pipes. For us to know what to look out for, let us jump into a quick science lesson! Up for it? Let us move forward!

1. Chromium

First off, we have chromium. This element is added to the manufacturing of stainless steel pipes to increase its non-corrosivity and anti-oxidation properties—two properties that we look for in hydroponic pipes.

2. Nickel

Nickel is another element that is an ingredient in stainless steel pipes. This element aids the durability of a stainless steel pipe.

3. Titanium and Niobium

Furthermore, titanium and niobium have the ability to prevent intergranular corrosion, also known as welt decay. This reaction happens during welding operations as a response to the high temperatures used.

What are the Different Grades of Stainless Steel Pipes?

There are two main grades of stainless steel pipes that can be safely used in hydroponics: 1) 304 and 2) 316.

The commonly-used grade is 304, also known as A2 based on the International Organization for Standardization (ISO 3506). This is a safe choice for hydroponic food production because it was proven safe for food preparation, storage, and dining.

On the other hand, 316 is the second most prominent type of stainless steel pipe and is used for food and surgical purposes.

The only difference between these two grades of stainless steel pipes is the presence of molybdenum. Molybdenum helps in hindering corrosion that is caused by chemicals.

304 vs 316 Stainless Steel

Stainless Steel Pipes vs PVC Pipes

Polyvinyl chloride pipes are better to use in hydroponics because they are easier to use and cheaper. They differ from stainless steel pipes in terms of material, common application, installation, and chemical hazards. However, both types do not easily corrode in ambient conditions and are reasonable options for a hydroponic system.

Feature	Stainless Steel Pipes	Polyvinyl Chloride (PVC) Pipes
Main Material	Iron	Plastic
Common Application	Laying pipelines Internal plumbing	Electrical insulation of cables Water supply
Installation	Fittings Flanges Welding	Glue Teflon
Corrosion	Does not easily corrode	Does not easily corrode
Chemical Hazards	Galvanic corrosion due to aluminum	Chlorine leaching in high temperatures
Can Be Used in Hydroponics?	Yes	Yes

At this point, I will not yet dive deeper into these aspects. Instead, these differences will be further compared in the last section to help you decide which one to use in your hydroponics system. So the best thing to do for now is to read further!

3 Questions to Answer Before Using Stainless Steel Pipes

Stainless steel pipes, as raw materials for nutrient film technique hydroponics, are not cost-effective, even in the long run. PVC pipes, on the other hand, are easier to work with, cheaper, and work effectively as the main material for most nutrient film technique systems.

Are stainless steel pipes cost-effective in the long run? How can you know if stainless steel pipes are for you? Answer the questions moving forward.

1. Which Material is Better for Hydroponics?

Factors such as heaviness and cost are key considerations in choosing building materials for any hydroponic system.

In choosing a nutrient film technique hydroponic system, one of the key criteria a hydroponic gardener must consider is the material used.

Ask yourself the following questions:

1. Are you up for a lightweight or a heavy system?
2. Would you like to invest high quality in raw materials (i.e., stainless steel pipes) or ready-to-use systems (PVC)?

If you like a lighter hydroponic system that you can move anytime, go for PVC-based hydroponic systems. If you are planning to establish a long-term hydroponics farm, and you have the capital for it, you can opt to use stainless steel pipes.

2. Which is Easier the Easier Hydroponic System To Install?

PVC-based hydroponic systems are easier to install compared to stainless steel pipes which need welding work.

As I mentioned a while back, there are readily-available PVC hydroponic sets available on the market. So, if you are looking for convenience, PVC nutrient film technique hydroponic systems got your back!

Learn more about PVC in our article is PVC safe for hydroponics? 

3. Factors to Consider to Avoid Possible Corrosion in Hydroponic System?

Stainless steel pipes can only corrode with the presence of elements such as aluminum. Whereas, PVC pipes can corrode at very high temperatures, specifically 100°C, which will result in the leaching of chlorine.

Now, knowing these factors that lead to corrosion, you must remember to not use aluminum along with stainless steel pipes. This may happen, for instance, when using aluminum screws to install your stainless steel. In the long run, the stainless steel will corrode.

On the other hand, temperature control is key for those who want to use PVC pipes in hydroponics.

   Learn more about how to control the temperature in our article on temperature. 

FAQs

Which stainless steel grade is best for hydroponics?

The 316 stainless steel grade is ideal for hydroponics because it is proven resistant to possible damages caused by bases, acids, and chloride (salt). It is also safe to use in food production processes, which is fit for its usage in growing hydroponic vegetables and herbs.

Is polyvinyl chloride (PVC) pipes safe for hydroponics?

Food-grade PVC is safe to use as tubes in nutrient film technique hydroponic systems. Commercially-available hydroponic systems are usually made up of unplasticized PVC or rigid PVC. These PVC types are also used in aquaponics, water station systems, and machines that are involved in food or beverage production.

Summary of Stainless Steel Pipes in Hydroponics

Stainless steel pipes is considered and used in hydroponics due to their durability, resistance to rust, and cleanliness. However, they are prone to galvanic corrosion, are heavy, and incur high initial costs.

Polyvinyl chloride (PVC) pipes, the traditional hydroponic material being used, are different from stainless steel pipes in terms of material, common use, and installation. However, both can be used in hydroponics. On the downside, both present potential chemical hazards.

In terms of practicality, stainless steel pipes are not recommended for hydroponics, especially for small-scale, at-home gardening. This is because they are more expensive, hard to install and reposition, and require technical work such as welding.

Sources

• “Galvanic Corrosion” by Zhang, X.G. in Uhlig’s Corrosion Handbook
• “Corrosion fundamentals and characterization techniques” Cragnolino, G.A. in Techniques for Corrosion Monitoring
• “Continuously killing bacteria on coated stainless steel — add bleach to recharge” by American Chemical Society in ACS Newsroom