How will this work?

I just bought Parks thermostat/mat (20 x 20) unit. I will put my hibiscus cuttings on it and set it for about 75 degrees. Then can I turn my thermostat down to about 65 at night without harming them? I will have to pay an arm and a leg to keep it at seventy all winter. I figure that I can recoup the price of the mat with money saved on the gas bill; I might even try 60.

Hi Gloria:
The first weeks are very important in a cutting's life. They need a constant temperature in the range 80-85 ºF. Less than that means they need more time to root and more time means more chances to rot.
Once you notice they have roots you can down the temperature to 60ºF. They won't grow too much but they will survive the winter.
There are some places in a house that keep a high and constant temperature. If you have room above the fridge that's a good place although you would need a fluorescent bulb to give them light. But light is cheaper than gas.

Regards

Carlos

Thanks, Carlos, I will check the top of the fridge and see if I can rig up ANOTHER timed flourescent light. I already have nine. I could use a goose neck lamp with a light bulb kind of flourescent light.

You can buy a regular light bulb for plants that will fit in your goose neck lamp. I have one that I use all the time.