Abstract:
The effect of heating the nutrient solution to 25°C was studied on a crop of early tomatoes cv.
Grenadier grown at night air temperatures of 18° and 13°C and a day temperature 20°C. Solution warming gave a large increase in root size, raised the levels of minerals in the leaf but did not affect the development of early fruit or the early yield.
The high night air temperature gave heavier early yields.
However by the end of the experiment the heated solution low air temperature treatment had caught up and produced 18.9 kg/m2 to the end of June against 15.9 kg/m2 for the ambient solution.
Conversely at the high night air temperature solution warming reduced the yield from 19.8 to 18.2 kg/m2.
Solution warming gave an increase in fruit size at both temperatures but at the high night air temperature it also gave a sharp reduction in the number of fruit.
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