let me go back and check exact temp range for you, but I do believe it is recommended to have your root zone warmer than your room temps...whole purpose for using a heat mat when cloning the semi-old fashioned way.

Look I have cuttings that look ;like total crap sometimes and then they root.

As long as stems are not getting 'Mushy'...don't worry. every strain takes it's own time...

lw