High-quality water is the foundation of a productive, resilient greenhouse. Yet too many operators wait until problems show up in the crop before they consider what’s flowing through their lines.
We 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.
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, 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.
Tip: Run tests seasonally. Municipal sources may fluctuate, and well water quality often changes after heavy rainfall or drought periods.
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.”
What it solves:
- 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
Design tip: RO systems should be sized not just for daily volume but also peak demand, redundancy, and flush cycles. Jim recommends membrane cleaning protocols and pretreatment (such as sediment filtration or softening) to extend lifespan and performance.
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.
Are you still giving the plant what it needs?
Operational considerations:
- 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 into the fertigation tank
Best practice: If reusing leachate, plan for dilution ratios. For example, some growers reintroduce return water at a 3:1 or 4:1 ratio with RO to maintain nutrient precision without risking buildup of sodium or pathogens.
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, reduce flow rates; it’s a silent problem until it’s not.
Signs you’ve got a problem:
- Uneven emitter output
- Fluctuating pressure in zones
- Drop in dissolved oxygen
- Foul odor in reservoir tanks
Solution: Continuous ozone dosing.
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 (chlorine dioxide, hydrogen peroxide) work too, but ozone is plant-safe, residue-free, and scalable across a wide range of volumes.
When to Bring in Water Experts
Timing matters. Jim says greenhouse teams often bring in NuStream after something goes wrong, not before. But the best outcomes happen when water system planning is integrated from the start.
“We’ve worked on installs, retrofits, and redesigns,” he says. “But the most efficient projects are the ones where we’re involved in the design phase alongside the greenhouse builder.”
What this means for operators: When you work with LLK on a design-build project, we don’t treat water as an afterthought. From site plans to fertigation zones, we help coordinate water strategy with partners like NuStream, so that irrigation, climate, and crop planning are all aligned from day one.
Final Word: Think in Cycles, Not Systems
The most successful growers aren’t just thinking about gallons in and out. They’re thinking in terms of feedback loops: where water quality, nutrient strategy, crop selection, and system maintenance are all part of the same cycle.
At LLK, we’re here to help you build greenhouses that work smarter across every input. That means better conversations early on, trusted partners like NuStream, and full-spectrum strategies that go beyond the spec sheet.
Got questions about water treatment or fertigation design? Let’s talk.
