“Water never spreads equally in the pot ball”

The knowledge institute for substrates RHP gives various water workshops to its members at the moment. Senior researcher Hans Verhagen has performed substrates research for over 25 years and explains the subject “What is in the pores; water or air?”. “The most important and most surprising conclusion is that water spreads differently in the pot ball than assumed until now. This makes another way of measuring the water content necessary”, according to Verhagen.

“We thought that water would always spread entirely. But that isn’t the case at limited watering. Not even at a pot ball of coir pith, a real water absorber. The water is fully absorbed, but then it doesn’t spread over the whole pot ball. Then as a result, the crop can stay behind unexpectedly”. During research at a short watering of 10 minutes with the help of an ebb and flow system, the underlayer absorbed 80% of the water and only 20% was absorbed by the toplayer. “So a sensor randomly put in the potting soil doesn’t give a right indication at all. That’s why it is important to measure with multiple sensors which are put horizontally in the pot.”, emphasises Verhagen.

RHP certified substrates guarantee an optimal start of the culture. It offers security that the substrate complies with the right quality demands concerning among others water and air content, pH and for example EC. It also guarantees that the substrate is pure and clean and that there are no risks for a safe application in the culture. The RHP quality mark secures the quality of growing media in the chain, from raw material production until processing and delivery at the company of the user.

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