Temperature
The optimal temperature for net assimilation rates in tomatoes is between 25 and 30 c (khavari - Nejad,1980). It does not seem to matter greatly in young plants if day and night temperatures differ. Relative growth rates of young plants responded relatively independently to the day and night temperatures with an optimum for both at around 25 c (Picken et al.,1986). The effects of changing night temperature on the relative growth rate are about half those of changing day temperature (Picken et al.,1986). If day temperatures are above optimal, a lower than optimal night temperature can compensate. If the day temperature is below optimal, within the range of 5 c, a higher night temperature can compensate (Calvert,1964).