ANTIRRINUM
It is important to choose a variety from the correct response group.
Snapgragons are heat and light responsive and are grouped as outlined below.
It can be grown under various light intensities provided a variety with a correct response group is selected.
Temperature affects the overall growth rate, but it is day length and quantity of light, which are the most important factors which influence flower initiation.
Group 1
Short days, low light and night temperature at 7-10 DC (mid-winter flowering in South Island)
Group 2
Short days, but longer than group 1, moderate light & night temperature at 10-13DC (mid-winter flowering in North Island)
Group 3
Medium to long days, moderate to high light & night temperature at 13-16DC (spring, summer, autumn flowering New Zealand wide)
Group 4
Long days, high light & night temperature higher than 16DC (forcing types for flowering under longest days & high temperature