An Instrument for Measuring the Firmness of Brussels Sprouts

The effects of CO₂ supplementation from November to early February on the winter bloom production of Sonia roses was investigated in a glasshouse divided into four compartments. A comparison was made between no enrichment and enrichment to a controlled level of 1000 vpm CO₂ with each treatment being replicated twice. For the period December-April, plants in the CO₂-enriched compartments produced 23 % more marketable blooms than those not enriched, the monthly increases ranging from 18% in December to a maximum of 31 % in February. Other beneficial effects .obtained from plants in the CO₂-enriched compartments were a higher proportion of first grade blooms, particularly in the shorter stem length categories, and a correspondingly smaller proportion of second grade blooms. The monthly increases in marketable blooms obtained in the CO₂-enriched compartments were the result both of a reduction in the numbers of blind shoots present and of the stimulation of greater numbers of axillary buds into growth.

At 1972–73 prices the monthly increases in cash returns obtained from the CO₂-enriched compartments ranged from 28p per sq m of bed area in December to 43p per sq m in February.