get the strong and healthy before planting outdoors, all the jump you can get on the veg cycle the better. iv seen em hit with frost in the first week of june before so dont get out to early. this year the weather is kinda screwy, it might be possible to get them out before june, but im not counting on it.
mixing up a supersoil will help a lot outdoors no matter what. just because its north doesnt mean its cold all summer. it will still hit high 80's 90's, and go days with out water. use some water crystals (the small granules not the chunky ones). and plan on making sure you dont leave them all on theyre own.
i prefer something thats going to finish early, the morning dew is nasty mold welcome matt.
watch out for rippers, them fukn fukrs...