| | What would you do if you are known for good quality cucumbers and the shipment has been returned because the blossom end turned soft. The picture below provides an idea of what I am talking about. The first thought was that something went wrong during shipping. Maybe the truck was too cold, but then cucumbers from other growers were alright, so that rules out the possibility of damage during transportation.
My second thought was that lack of calcium, or boron or maybe potassium could have caused the problem with the fruit. The results of the leach ruled that out, as well. All macro nutrients and micro nutrients were within normal range. pH and E.C. were also in the range.
A visit to the greenhouse helped solve the problem. It was the computer screen which yielded some clues. The moisture deficit which is expressed in grams/cubic meter of air was 2.4, 1.6, and 1.3 for 3 days. Moisture deficit is a calculation made by combining temperature and relative humidity. The higher the temperature and relative humidity, the lower the moisture deficit, meaning that ability of water from leaves to go into the surrounding air will be less. If moisture is not lost from leaves to the air, then transpiration is reduced and roots don’t develop in the growing medium. Calcium uptake is the first one affected by lower moisture deficit and unlike potassium, calcium has to be provided to cucumbers fruit, on a constant basis. Like potassium, it is not stored in the leaves, and it is immobile. Calcium is part of the cell walls and once fixed it cannot be moved to other areas.
A recommended moisture deficit for cucumbers is in the range between 3 and 7 and that is achieved by maintaining proper temperature and relative humidity. What is worth remembering is that what you do in the greenhouse affects the post harvest quality of cucumbers and other vegetables. |
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