Demonstrating how increased irrigation and rainfall affects crop results

September 23, 2019

Climate norms seem to be changing and the trend appears to be colder and wetter springs. As expected, the 2019 growing season was no exception and gifted us with one of the wettest springs we have seen to date. These wet and cold springs can challenge our traditional production practices and require us to reconsider our “business as usual” production techniques.  

This year, Gro-Bark designed a trial to demonstrate how increased rates of irrigation, in combination with higher rainfall, could result in unintended nutrient leaching from a crop. Hydrangea macrophylla plugs were potted into a trade gallon pots in one of three mix recipes:

  1. Bark/peat moss
  2. Bark/wood fiber
  3. Peat moss/perlite

The plants were watered under four different irrigation rates; 250ml; 500 ml; 1000; and 2000ml daily(Monday to Friday). In all three growing mixes, media EC decreased and pH increased as the irrigation rate increased. The nitrogen content of the leaves also decreased as irrigation was increased. Interestingly, phosphorus content was deficient in the leaf tissue analysis in all treatments and under all irrigation rates.