Germination and growing Temperatures - Ask Extension
Hello,
All publication I see, including UMD-Extention, indicate optimum plants growing Temperatures -I grow vegetables- but what about soil temperatu...
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Germination and growing Temperatures #924786
Asked February 19, 2026, 11:31 AM EST
Hello,
All publication I see, including UMD-Extention, indicate optimum plants growing Temperatures -I grow vegetables- but what about soil temperature? I start my seeds inside and then move them to the garden. I control both soil and air temperature until plants are ready to go outside. My question is; what is the best Soil -not the air- temperature after germination (until they have at least 3 leaves).
For example, for Pea and Broccoli I set the soil temperature at 85F until they come out of the soil. Then I set the air temperature to 65F but I do not know what temperature should I set for the soil.
Montgomery County Maryland
Expert Response
For indoor seed starting, raising the temperature of the root zone (potting mix) a few degrees above the ambient temperature will suffice, at least for the typical range of indoor temperatures in a heated home. In general, potting mix temperatures should be in the 65-75 degree range; 70 degrees can be a target, especially for seedlings post-germination. Cool-season crops, like green peas, can handle cooler temps, though still may germinate with the greatest speed closer to 70 degrees or so; in their case, too much warmth may slow them down, as they prefer cooler conditions. We don't recommend warming the root zone to 85...that sounds too high, and it might stress plants (or at least dry out the mix faster, and potentially increase vulnerability to root infections).
Miri
Miri
