I live in Sourthern NH about 200 mi east of you. I select a 90 day to maturity variety, I start about 12 weeks early so I have a 12 to 16 in plant in a 4x6in pot (Mostly newspaper) to reduce root trauma at transplanting. You live in Zone 4 Last typical frost May 20th and first normal ?? is Sept 10. Normal plant out is Memorial Day And start thinking about frost covers on Labor Day For paste tomatoes try the Amish Paste, lot more flavor and larger. Needs staking for 6ft plant, and a lot of sucker growth Byron