ISHS Acta Horticulturae 481: International Symposium on Growing Media and Hydroponics
COCO COIR VERSUS GRANULATED ROCKWOOL AND 'ARCHING' VERSUS TRADITIONAL HARVESTING OF ROSES IN A RECIRCULATING SYSTEM |
| Author: | Theo J. Blom |
| Keywords: | arching, bending, coco coir, coco peat, hydroponics, recirculation, roses |
| Abstract:
Cut roses (cultivars 'Sonia' and 'Laser') were grown for two years in a recirculating system in either coco coir or granulated rockwool substrate using either the 'arching' or the traditional harvesting technique. Flowering stems were cut 3 cm above the knuckle using the 'arching' technique or above the first or second five-leaflet (conventional) above the knuckle with the traditional harvesting technique. The fertigation solutions were sampled every 6–8 weeks, analyzed for macro and micro elements and completely renewed. Plant tissue of harvested shoots was also analyzed every 8 weeks. During the first year, coco coir produced about 15.6% more marketable (>30 cm in length) stems as well as 18.0% more fresh weight compared to granulated rockwool, while there were no significant differences between the substrates during the second year. The arching technique produced 15 cm longer and 47% heavier stems but fewer (-29.3%) marketable roses than the conventional harvesting technique. Fresh weight of harvested roses was similar for both techniques. Solution analysis indicated that phosphate and micro nutrient concentrations decreased while calcium, magnesium and chloride increased with recirculation. There were higher levels of micro elements in rose stems grown in coco coir than those grown in rockwool. The ratios between nutrient removal (from harvested stems) and net supply (irrigation) were 0.37, 0.24, 0.30, 0.21, and 0.29 for N, P, K, Ca, and Ma, respectively. | |
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