Long-term cultivation of cut gerbera in peat-based growing media.

摘要

Peat substrates of many years' standing are rarely used in greenhouse cultivation. Our aim was to develop a peat based growing medium suitable for long-term cultivation of cut gerbera. Cut gerbera 'Ruby Red' plants were grown in 3.5-litre pots in the greenhouse for 2.5 years in 5 peat based growing media and perlite. The peat substrates were extra coarse Sph. peat (AApeat); peat granules 40%+coarse Sph. peat 60% (PG40); peat granules 10%+coarse Sph. peat 90% (PG10); peat granules 10%+Eriophorum peat 90% (PG10+E); dark peat granules 30%+coarse Sph. peat 70% (DPG30). Supplementary lighting for 10-12 h d-1 with 140-180 micro mol m-2 s-1 PPF was supplied and the CO2 level was kept at 500-600 ppm when the vents were closed. The total yield over 2.5 years was highest (approx. 430 flowers m-2 year-1) in DPG30, perlite and PG40 and lowest in AApeat and PG10+E. The yield in AApeat decreased after the first year of cultivation and remained at that low level until the end of the experiment. In contrast, the yield in PG40 started to increase after one year. The prolonged cultivation time reduced the yield quality in all growing media. Physical parameters at -10 cm suction were measured. These parameters changed only little during the experiment. Irrigation, soil moisture, pH, EC and NO3-N were recorded regularly. Peat based substrate stabilizers held their structure throughout the 2.5 years of cultivation.