Alstroemeria production is influenced by thinning method and frequency

Abstract

The Alstroemeria cultivars King Cardinal and Diamond were grown with soil cooling for 50 weeks under high pressure sodium lamps at a PPFD of 150 μmol m −2 s −1 (photosynthetically active radiation, PAR) for 20 h per day. The total shoot production and the morphology and yield of flowering stems from plants subjected to different thinning practices were recorded. For both cultivars, the total shoot production was higher when stems were thinned and harvested by cutting rather than pulled from the rhizome. The yield of flowering stems was not influenced by technique for thinning and harvest. For ‘Diamond’ the highest yields of stems of marketable quality occurred when 30% of the shoots that remained after harvest were removed every third or every fifth week. For ‘King Cardinal’ the optimal thinning seemed to be a removal of 30 or 60% of the shoots every fifth week. The length of the harvested flowering stems varied to some extent seasonally, and hard thinning resulted in longer stems than more lenient thinning did.