To reduce the emission of fertilisers and pesticides from soil bound chrysanthemum production, research over the last four years has focussed on developing soilless systems. The research was funded by the Product Board of Horticulture and the Dutch Ministry of Economic Affairs.

Three potential systems were developed, being a deep flow system, a root spray system and a substrate cassette (a slim strip of substrate). Studies for further development focussed on EC-strategies and substrate selection. EC was found to be of usefull influence in plant steering.

Using a strategie of lower EC at start (EC 1,2) and increasing the EC-levels to 2,8 at 8 days after start of the short day phase would decrease the length of the flowers - making chemical growth reduction obsolete. Largest flowers were grown when production started at high EC levels and was lowered at 8 days in the short day phase. As for substrate, the mixture of peat/perlite gave stronger development than production on cocos or sand. This could nog be explained by differences in oxygen availability in the substrates. Reducing the substrate volume from a column of 3 cm wide to 1,5 cm wide reduced growth.

Souce: Unit: Wageningen UR Glastuinbouw - 28 Jan 2013