The institute has been testing an environmentally friendly system called "deficit irrigation", which replaces approximately 80 per cent of the water the plant loses through transpiration. This stimulates the plant to produce hormones that can influence plant "robustness" and increase tolerance to the stresses encountered during distribution and retailing.
The technique reduces water use and reliance on plant growth regulators (PGRs) used in normal commercial production.
EMR found leaf and bract drop of poinsettias grown using this method were cut by 50 per cent and 90 per cent respectively, compared with well-watered plants. The study was funded by DEFRA.
The results come after experiments were conducted last season at Kent-based Staplehurst Nurseries, when Regulated Deficit Irrigation (RDI) was used on a commercial scale for the first time.
A six-week RDI regime used during the period of rapid growth reduced stem extension, so plant heights were well within specifications at simulated market date. RDI-treated plants received only one PGR spray shortly after "pinching", compared with the nine or 10 sprays needed to control height in the conventionally irrigated plants.
Research leader Dr Mark Else said: "Our research at Staplehurst Nurseries has shown that growers could use RDI to produce poinsettias with excellent shape and colour, as an alternative to PGR spray programmes."