Effect of spacing and irrigation interval on growth and yield performance of purple cabbage

Florida is ranked third in total cabbage production in the U.S. and it is traditionally grown on bare ground with subirrigation. The use of plastic mulch and drip irrigation is widespread for other vegetable crops and can enhance water and fertilizer use efficiency and yield. The objective of the study was to evaluate plant growth, yield and head quality traits of cabbage using three plant populations and four planting dates on a plastic mulch system. Cabbage was transplanted in mid September (SEP), mid October (OCT), early November (NOV), and early December (DEC) in the 2013–14 and 2014–15 growing seasons, spanning the entire planting season for commercial operations in northeast Florida. There was no interaction among planting dates and plant populations for total and marketable yields or biomass. For both seasons, the SEP and OCT plantings showed a faster growth rate than NOV and DEC during the first 70 days after transplanting; however, differences in total biomass accumulation were only seen in 2013–14. Biomass decreased quadratically in 2013–14 with an increase in in-row spacing. Average marketable yield for both years was 62.7, 60.5, 46.2, and 58.6 Mg ha−1 for SEP, OCT, NOV and DEC, respectively. As plant population decreased, marketable yield increased linearly in 2013–14 while no differences were seen in marketable yield among plant population treatments during 2014–15 season. Plant growth rate and yield were correlated to growing season average air temperature and solar radiation. The SEP, OCT and DEC planting dates benefited from more favorable weather conditions, while low air temperatures and reduced solar radiation had a negative effected on cabbage yield for the NOV planting.