Rock Cold Days...Mix Gasoline with Diesel?

[Carrameow]

Its been 12 to 17 degrees here at nites and both of my cars are diesel...
Besides adding Diesel additive, I'm looking for a more reliable solution to ensure my car starts in the morning.
Someone told me i can use a 10%/90% Gas Disel mix on cold days.
I dont trust anyones advice unless I hear it several times...