Hops need around 30 total days of freezing temperatures in the off season to go dormant and come back again in the spring. You could probably get away with less but your yield may suffer. Also you should get a soil test (agricultural not a lawn test) on the ground you plan to plant them in. Your local extension office should have the kits. This will give you a starting point in terms of what the soil pH is, NPK content and micro nutrient content. Based on your soil test results you can work to adjust your pH level and decide if you need any fertilizer. If you get a soil test, there should be a box for "next crop grown" where you can mark in HOPS, so when the results come back they usually contain fertilization rate recommendations based on the next crop to be grown. If "HOPS" is not an option, check "CORN" it has a similar N uptake.
Jason