Is cleaning the same as disinfecting?

No, and treating them as one is the most common failure. Every practical disinfectant is an oxidant, and it reacts with organic residue before it reaches the pathogen. A surface that has not been cleaned first is effectively untreated, however much product is applied to it.

Can a growing system be fully disinfected?

Not by chemistry alone. In measured trials on infected roots, Fusarium survival after treatment ranged from a fraction of a percent to over forty percent depending on the agent, and none achieved complete disinfection. Nematodes recovered after treatments assumed to have killed them.

Which chemicals must never be combined?

Chlorine and acid. The reaction produces chlorine gas, and it also swells and damages the silicone membranes inside pressure-compensating drippers. Rinse thoroughly with clean water between a chlorine treatment and an acid one rather than shortening the sequence.

Greenhouse Hygiene Protocol — DutchGreenhouses

Q: Why does hygiene matter more than water treatment for viruses?

Because the water route is not the main one. For tobacco brown rugose fruit virus the research states plainly that water is unlikely to be the most efficient transmission route and that mechanical spread on hands, tools and clothing dominates. Treating water while people move freely addresses the smaller problem.

The route in is rarely the one that gets engineered against

Growers invest heavily in treating water and excluding insects, and then a virus arrives on a pair of hands. For tobacco brown rugose fruit virus the research is explicit that water is unlikely to be the most efficient transmission route and that mechanical spread — hands, tools, clothing, crop work — dominates. A hygiene protocol is the control for the routes that no equipment covers, which is why it returns more per euro than almost anything else in the crop-protection budget.

Two rules govern it and both are routinely broken. Cleaning and disinfecting are different operations: every practical disinfectant is an oxidant, and organic residue consumes it before it reaches the pathogen, so a surface that has not been cleaned first is effectively untreated. And contact time is longer than most people assume and non-linear — past the point where the oxidant is spent, leaving it on achieves nothing. Dutch guidance is blunt that skipping the cleaning step makes the effect negligible.

The uncomfortable finding is that no chemical fully sterilises a growing system. In measured trials on infected roots, survival of Fusarium after treatment ranged from a fraction of a percent for formaldehyde to over forty percent for one widely used product, and none of the agents tested achieved complete disinfection. Nematodes recovered after treatments that were assumed to have killed them. The practical conclusion is that hygiene reduces inoculum rather than eliminating it, and a protocol written on the assumption of elimination will disappoint.

So the protocol is procedural before it is chemical: a defined route for visitors, dedicated clothing and footwear, tool discipline, a real crop-changeover sequence, and one safety rule that is not negotiable — chlorine and acid must never be combined, because the reaction produces chlorine gas and destroys the silicone membranes in pressure-compensating drippers. DutchGreenhouses® designs the facility layout, the service building and the irrigation system so those procedures are physically possible to follow. Get in touch to discuss hygiene for your facility.

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