Heating,
programmed at 6pm (on) to 6am (off) matched
adequately
with sunset and sunrise with always less than
50 mol m−2 s−1 of PAR (photosynthetic active radiation) at 6am
and 6pm and full night 30 min before 6am and after 6pm. At night,
during the heating period (56 days) and despite some variability,
mean NT increased by about 1.9 ◦C in rings equipped with heaters
compared to control rings (Fig. 1, Table 1). Overall throughout the
whole crop cycle, the increase in NT was about 1 ◦C. Minimum tem-
perature (always recorded at night) was less affected by heating