This roughly corresponds to the number of seed produced per capitula, depending on pollination events. Subspecies readily hybridize among themselves. All of the taxa, except for a few accessions of V. galamensis spp. Most plants will flower after receiving 5 to 10 short days of 11h light and 13 h dark periods. Accessions of var.
Plants flower indeterminately.
A planting density study at Maricopa, Arizona, was made in 1994 with hybrid lines by varying plant spacing within rows, which were 1m apart. Although plants flowered earlier in the 0.60 m spacing, these plants appeared to be the poorest performers toward the end of the season. As plants mature, the stems become brittle. There is an advantage to spacing plants closer to provide support for each other. The closer spacing may also force flowering on the top and outside canopy, achieving better plant architecture for harvesting.