Cry Havoc

We’re brewing a 10 gallon batch (21 lbs 2 row/ 1.5 lbs crystal 60) and we were going to do a split and lager half and ale the other. My question is what is the best temp for lagering? I live in Pennsylvania and would like to store in in my garage (which should be in about the 40-50 degree range, is that to cold to do primary in?

depends on the yeast, should say on the package. Most of my lagers I ferment at 50* (beer temp, not ambient). Put your fermenter in a water bath to minimize fluctuation if you are relying on ambient temperatures.

Those temps sound perfect for a lager. 40F is a little low, but the yeast will still do their thing. I agree with Pietro about the water bath to minimize temp swings.