Pre-treatment.

Making any water source crop-safe, before it ever reaches the crop

Pre-treating irrigation water is fundamental to a successful irrigation system. It is called “pre”-treatment because, chronologically, it is the step before fertilising — and because irrigation water comes into direct contact with a valuable crop, it needs to be controlled from start to finish. Continuously analysing the source water and anticipating its variation is what keeps a grower genuinely in control of the greenhouse.

Four characteristics of the source water need to be managed, each with its own proven method, and in practice these technologies complement one another. The first is pH: controlling the pH of incoming water prevents algae and pathogens, particularly when water is stored in a tank or basin beforehand, and is handled in a shunt system that continuously circulates the water and doses acid or lye to hold a stable level. The second is micro-organisms, where there are two routes — UV treatment, in which pressurised water passes directly under UV lamps that kill organisms, and ultra-filtration, our system of choice, which removes them entirely so there are no residues left to feed new growth, with lower energy and maintenance costs than UV. The third is particles and sediment, most commonly filtered out with a maintenance-free paper-belt filter (flat-bed, deep-bed or hydrostatic, selected on capacity and contamination), where the filter paper sets the particle size removed. The fourth is water hardness, managed with a water softener to reduce chloride — installed before any tanks and systems, since hardness directly shortens the life of pumps, ducts and valves and makes fertilisation less efficient. For the most demanding inputs, reverse osmosis strips all micro-organisms, particles and minerals, giving a blank slate for precise (if costlier) fertilisation.

Which chain you need depends entirely on the source. City (tap) water is the most stable and reliable, already treated and typically at ambient temperature, but it is the most expensive and can be high in chloride. Surface water varies in quality and quantity and demands more complex treatment; well water is often consistent and mineral-rich but must be tested regularly for contaminants; rainwater is an excellent source collected straight from the greenhouse roof, but its availability is inconsistent and needs a backup. Water temperature matters too: cold water holds more dissolved oxygen while warm water breeds micro-organisms, so the preferred choice is ambient water at 15–20°C, managed through a heat exchanger tied to the facility's heating or cooling system. A source-water analysis is always the starting point — the cleaner the input, the simpler the chain. Get in touch to have your water assessed.