@Alfi: Meine Tochter die Agrarwirtschaft studiert kann sich nicht vorstellen, wieso die Melonen unter 20° Bodentemperatur schlechter Wasser aufnehmen können. So etwas ist doch normalerweise nur bei Frost der Fall. Wo hast du das gelesen?
LG
Das Buch heisst Cucurbits und ist ein Buch uber den Agrar-Anbau von Melonen, Kürbis, Zucchni etc. Sehr fachlich gehalten.
Hier der entscheidende Absatz:
"Cucurbits are very sensitive to low root-zone temperature, which increases susceptibility to diseases. At temperatures below 20 degrees, water uptake may be restricted and the plant injured or killed by drought, even though soil moisture is ample.
.....
Kramer investigated the relationship between soil temperature and transpiration in watermelon plants, finding, that only 20 and 50% as much water was absorbed at 10 and 15 degrees, respectively, as at 25 degree. Decreased absorption at low temperatures appears to be the result of several factors, including decreased root growth, lower respiration rates, increased viscosity of colder water and decreased permeability of root cell membranes. Root permeability in watermelon decreases when temperatures fall below 22 degrees, with water uptake decreasing most rapidly between 18 and 16 degrees."