Watering Rosemary in Indiana

I have recently built a greenhouse and have successfully started rosemary plants from cuttings. Living in the midwest, northern Indiana, USA, we are trying to keep the temperature in the greenhouse cool, (35-40 degrees Fahrenheit), in order to let the plants go dormant. I am confused about how much water the rosemary plants need in these cooler conditions. We have had an unusual number of bright, sunny days on which the temp.in the greenhouse will rise to 60 + degrees, then drop back down to low 30s Fahrenheit at night. I have read not to water them until they begin to wilt and I have read to not let their roots get dry. Also, what type of soil would you recommend?

Since the plants are not growing at the cooler temperatures, they should be kept a bit drier than in the summer, but never allowed to dry out. Waiting until they wilt is playing Russian roulette with the plants! Also since the plants are not growing, the stems are not soft anymore and that makes it very hard to tell when the plants are starting to wilt!
Rosemary likes a slightly alkaline, well-draining soil. You might wish to consult our web-site under Q&A and search for "rosemary" for lots of discussion of cultural problems with rosemary.