Greenhouse advice please

I have decided to try a greenhouse grow and have a few questions. First some needed data:

I will be building a PVC pipe ghse. Want to go "in ground" probably in February. I live in Northern California (Redding). It is normally about 40F at night and a high of 65F during the day. I plan on having clear plastic and will heat with a kerosene heater to keep the temp resonable (just hate to see the ladies shivering, nipples hard and all that...) I have all the details worked out (venting, humidity, etc)

The the main decision point for me at this is - - the type of plant.

I figure I'll have room for ten or more, and don't mind trying different seeds. But, I need ideas and feedback. Should I go 'autoflower'? I have the technology and ability to do a light deprevation program the last few weeks to get them to flower - but, if I don't need to, I don't wanna.

Who here has greenhouse experience in a similar climate? Who can give me ideas, warn of pitfalls, etc.

Instead of using a heater. Fill black plastic pails and jugs full of water, make sure the sun shines on them in the greenhouse and passively keep your greenhouse heated at night by the heat retained in the water jugs.

I was only thinking of using a heater because it adds CO2 to the air.

So, what kind of seeds?