Climate :-
Rapeseed and mustard are crops of temperate climates, but these can also be cultivated at higher elevations in the tropics. Crop requires about 18-25°C temperature, low humidity, practically no rains specially at the time of flowering. The crop growth is optimum at <25°C, while it ceases at less than 3°C and >35°C. Rainfall, high humidity and cloudy weather are not favourable for the crop during winter, as such conditions would invite aphids. However, under rainfed conditions, 1 or 2 pre-flowering rains help in boosting the grain yield. Excessive cold and frost are harmful to the crop. Toria is more liable to suffer from frost and cold. Therefore, it is usually sown earlier, and harvested before the onset of frost. Rapeseed and mustard are long day in photo-periodic response. They require an annual precipitation of 40-100 cm. These crops also do not tolerate waterlogging.