The business grows 9ha of peppers and 3ha of tomatoes under glass in the Lea Valley on the Essex/Hertfordshire border. Finely balanced margins are dependent on achieving top yields and quality, so there is no room for error when it comes to yields and quality. Every plant’s needs for water and nutrition must be met exactly using four drip irrigation networks across the site, so Gary made it a priority to investigate what was happening and putting it right.

Closer inspection revealed that the system was becoming clogged with biofilm, a layer of organic and inorganic material that lines the inside of pipes and emitters.  The problem had been building over several years since the irrigation system was installed, restricting water flow and leading to uneven application across the site, and occasionally blocking drippers completely. Biofilm also harbours many pathogens, including bacteria, fungi and oomycetes, which can multiply and eventually infect plants. “I noticed higher than usual levels of pythium and phytophthora, particularly in the peppers,” says Gary.

Emitters associated with dry slabs were also changed to ensure drippers were working effectively. Once the shock disinfection was complete, the irrigation systems were continuously dosed using a very low dose of Huwa-San TR-50. Six pumps, two for each for the larger glasshouses and a single one for each of the smaller glasshouses, were installed to ensure a constantly calibrated supply of Huwa-San TR-50 to the irrigation networks.

Hydrogen peroxide test strips showed the product was getting right through to the last drippers in the system. Water testing carried out by Nigel, six weeks after the plan was initiated, underlined its efficacy, revealing a 100% reduction in total viable count, a test that estimates the level of microorganisms in water.  “Nigel is due to come back to check levels, and I’m pretty confident all will be well,” says Gary. “Plant growth and fruit size is certainly more even and we’ve seen a drop in the amount of class 2 fruit compared with last season.”