12 september 2025
RHP sees a clear increase in the number of reported damage cases in crops. In 2024, 22 cases have been registered, compared to 13 in the previous year. At the first signs of growth problems or a report of damage, RHP advises securing counter samples immediately, so that these are not disposed of after the minimum storage period of 6 months.
After the production of a batch of RHP-certified substrate, substrate producers must take a counter sample of at least 5 liters and store it for a minimum of 6 months. In practice, however, it turns out that in cases of crop damage the counter sample is sometimes no longer available, because the storage period has already expired. Often, the damage had started earlier and was reported to the substrate supplier.
RHP therefore advises certified companies to establish an internal protocol in which counter samples are secured at the first report of seemingly harmless or small signals of growth deviations, growth problems, or damage. Such a protocol prevents samples from being disposed of immediately after the minimum storage period and being unavailable during damage investigations. It is important that both quality staff and sales staff are aware of this.
Although this is an advice and not a certification requirement, it can be very helpful in tracing the cause of damage or in ruling out the substrate as the cause. Also read our earlier advice: Crop damage? Involve RHP fast for proper substrate research (9 May 2025)
