ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
SOIL COOLING FOR FREESIA'S |
| Authors: | T. Dijkhuizen, G.P.A. van Holsteyn |
| Abstract:
The time from planting out to picking of Freesia depends strongly on the growing conditions. Especially the soil temperature around the main shoot apex is very important. Directly after planting out the optimum soil temperature is 15 – 18 °C. In the Netherlands in summer the soil temperature in glasshouses is normally higher. To keep the soil temperature approximately on the optimal level the glasshouse is well ventilated and shaded while the soil is covered with a mulch. Often sprinklers are used also. In spite of all these measures the soil temperature is too high in many summers. During a number of years we have done experiments to lower the soil temperature by water-cooling. In these experiments the pipes were placed 40 cm deep in the soil. The distance between the pipes was also 40 cm. The cooling-capacity was 19 Watt/m2. On a depth of 10 cm the temperature was lowered 3 °C. The daily fluctuation of the temperature was not influenced. In our experiments we planted Freesia corms and cormlets in June and July. A lowering of the soil temperature with 3 °C accelerated the picking period for 2 to 6 weeks. | |
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