What does "optimum germination temperature" mean to you?

[JerryHaskins]

This is not specific to tomatoes, but when looking into planting seeds, I see guidance regarding the optimum germination temperature.

That is especially true with regard to spinach seeds.

Now, I suppose that means "the constant temperature that the seed would like to be at while it is germinating."

I can kind of control the temperature of seeds in peat pots and trays.

But if I want to plant seeds directly in my garden, the daily high and low temperature ranges this week from 91 degrees in the daytime to a low of 55 degrees at night.

That's a 36 degree swing over 24 hours and is typical for Mississippi (zone 8a) in the fall.

I am not sure what the soil temperature is in my garden---but I would guess that the shallow soil in full sun would exceed the air temperature high in the daytime, but might not get quite down to the low at night.

So what do youall do with regard to "best germination temperature"?

I.e., what temperature do you go by when deciding when to plant?

(I know---I am suppose to find the date of the first or last freeze and back up so many days. But that gets hard to do.)

Thanks.