What time of year to germinate seeds for planting outdoors and also in greenhouse?

Basically i understand small plants need to go into the outdoor site around the start of May, being in the UK.
So when should i start germinating the seeds??
Do they need to be about 6 inches before i put them in the ground and if so how long will it take to get them that high?
Also i want to put an Autoflower into a small greenhouse. When should i start to germinate that one? I was just going to start them off in a window and then in the small greenhouse before i take them to the site.
I'm doing a Advanced Biodiesel Mass Autoflowering Feminised Seed in the small greenhouse, and some Purple Maroc outdoors.

Thanks in advance for your tips!!

Where I live in the north east U.S. it's about the same time here that we can plant outside. I started 5 jack herer ,3 big bang, 4 white widows last friday, but this was so i can get some clones before i plant outside. I would think if you started yours about 1 month before you planned on moving them to the location you should be more than good. just remember to acclamate(?) them to the weather first. As far as the auto I dont really know. I'm pretty sure somebody will have much better advice than me.Good Luck

cloning sounds like a good idea considering how expensive the seeds are! i'll start a seed now and give it a go. i've been reading about lot's of different ways to germinate the seeds, and i think i'm going to go straight to soil with them. i don't want the added risks involved in moving them around so much... just grow them in fibre cups that i can plant straight into bigger pots/ or the ground itself. there's so much info regarding fertilisers etc i'm tempted just to do it as natural as possible for my first grow. my head is swimming with so much f@cking info i feel as clueless as when i first started reading about it all. what is it they say? the more you know, the less you understand... or something along those lines

I know what you mean. I like the KISS rule myself. Keep It Simple Stoner. I've seen it on here in a couple of threads and i've been told that for years. I did a Sour Deisel last year outside with no nutes. It was a little girl but the taste was awsome! It was the first 1 I ever did with just water. I dont think that will work indoors as it did outside. From what I understand is it will pull what nutes it needs from the soil around it and the rain.