Smart Water Treatment and Reuse Strategies for Modern Greenhouse Growing
High-quality water is the foundation of a productive, resilient greenhouse. Yet too many growers wait until problems show up in the crop before they consider what’s flowing through their lines.
LLK Greenhouse Solutions recently spoke with Jim Baker, founder of NuStream Filtration, to explore the science of high-purity water in commercial horticulture, why reverse osmosis and fertigation strategies are evolving, and what greenhouse teams can do today to future-proof their irrigation systems. Here’s some of what they learned:
Start With the Water You Actually Have
Before you can design a system that works, you have to understand your source. And, as Jim points out, that’s often harder than it sounds.
“We always start with an honest-to-God water analysis,” he says. “And not just pH or hardness. You need organics, microbiological, and ionic content. Without that, you’re just guessing.”
Don’t settle for a basic water test. Request a full-panel lab report that includes:
- pH
- Electrical conductivity (EC)
- Total dissolved solids (TDS)
- Sodium, chloride, bicarbonate
- Calcium, magnesium, potassium
- Iron, manganese, sulfur
- Nitrate, phosphate, ammonium
- Total coliforms and heterotrophic plate count (HPC)
The full gamut of information is important. High sodium can cause osmotic stress in crops. High bicarbonates raise the risk of emitter clogging and interfere with acidification. Elevated iron or manganese can stain foliage and block filters. Even trace contamination can throw off nutrient uptake, especially in hydroponic or recirculating systems.
Why Reverse Osmosis Still Matters
While newer treatment methods like nanofiltration or UV oxidation exist, reverse osmosis (RO) remains the backbone of high-purity systems in horticulture.
“RO is still one of the best tools we have to remove a wide spectrum of contaminants,” says Jim. “Especially when paired with ozone or softening.”
Some of the ways that reverse osmosis helps include:
- Lowers EC, giving you full control over nutrient formulation
- Removes most ions, organics, and biological contaminants
- Creates a uniform water profile, critical for multisite operators or cultivars sensitive to specific salts
The Complex Math of Water Reuse
Recirculating irrigation water sounds simple. In practice, it’s anything but.
One of the biggest questions that Jim and the NuStream team will ask is, “How much fertilizer is still in your water when you collect it?” Different crops pull nutrients at different rates. And once you recapture it, you’re blending it with new water and new nutrients.
So, are you still giving the plant what it needs?
Operational considerations include:
- Use inline nutrient sensors or bench-scale sampling to measure nitrate, phosphate, and EC in return water
- Track daily irrigation volume vs. crop uptake to estimate true retention
- Store reclaimed water separately and treat it before remixing it into the fertigation tank
Avoid reuse in crops prone to root pathogens unless you have robust disinfection in place.
Biofilm and the Blind Spots of Maintenance
Even the best system won’t stay efficient without proper upkeep. One of the most common pitfalls? Letting biofilm take hold in the pipes.
Bacteria are extremely adaptable. They attach to the inside of tubing, coat emitters, and reduce flow rates; it’s a silent problem until it’s not.
Signs that you’ve got a problem include:
- Uneven emitter output
- Fluctuating pressure in zones
- Drop in dissolved oxygen
- Foul odor in reservoir tanks
The solution that Jim proposes is continuous ozone dosing. So, why ozone?
- It oxidizes organic compounds and neutralizes most bacteria on contact
- It leaves behind oxygen, which supports healthy root development
- It can be injected inline or used to sanitize tanks and emitters between crops
Other methods, such as chlorine dioxide and hydrogen peroxide, work too, but ozone is plant-safe, residue-free, and scalable across a wide range of volumes.
For more smart water strategies from Jim Baker and the NuStream team, please read the original article found on the LLK Greenhouse Solutions website.
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