how cold did it get.

I don't mean to sound stupid but is the water turned on. I get alot calls when it is something that simple. If the water is on you need to check to make sure the fuses in the controller are still good. If the fuses are still good then you need to take a digital voltmeter and check to make sure that you are getting somewhere around 24 volts AC on the outputs of the controller. Meaning, manually turn zone 1 on and put the black test lead into the COM connection and the red test lead in the #1 connection port. You will need to remove the 2 wires that are in there first. If you are not getting 24 volts then it is probably the controller. Being a Toro Greenkeeper you might be able to return it where ever you purchased it from if it is not too old. If you are getting 24 volts then let me know and I'll let you know what else to try.