So i harvested my Cascade hops a few weekends ago. didn't weight them but got 2- 5gal pails of them from my second year plant. i laid them out on old window screens for about 5 days to dry with a fan blowing air around in my garage. once dry i tossed them in ziplock bags, squeezed as much air...
that cold will not kill the yeast, it only slows them down.
You would need to add Campden tablets. i'm not a pro on this so hopefully someone else can chime in with a better answer.
i use mr. malty for the number of yeast cells and then i use a chart from BillyBrew for the steps.
i have been doing 2- 2L starters to get 300billion cells, atleast according to the chart. never actually counted them myself.
if you are using fertilizer, try to keep it off the plant best you can. Some fertilizers will burn you plant so bad you can kill them. i lift the plant greens off the soil and sprinkle around them.