Spinach Handbook

Day 0 Temperature
The temperature within the germination area is maintained at 20^oC (68^oF) during the first 24 hours.  It is imperative to keep the seed moist.  A lower temperature, in conjunction with lower light levels and a high humidity, help prevent the seed from drying during the critical germination period.

After 24 hours the seedling has begun to germinate and the temperature is raised to 25^oC during the 12 hour photoperiod.  The temperature is dropped to 20^oC (68^oF) during the dark period.