Spinach is a cool weather crop. Seeds prefer to germinate in cold weather. Optimal soil temperature for emergence is 10~18 °C/50~65°F. It can be planted when soil is workable in spring. Higher soil temperature ( over 20°C/68°F) may result in sharp decrease in germination rate. Seeding in summer is not recommended.
Spinach tends to bolt (seed-stalk development and flowering ) as day length, temperature and plant density increase. Water stress and inadequate nutrients increase bolting risk. Exposure of young plants to low temperature (4°C/40°F ) also increases the risk of bolting.
Approx. 70~100 seeds per gram/ 10~14 gram per thousand seeds (M).