The seeds will germinate anywhere there is warmth and moisture. don't plant them too deep, just about 1cm. For height issues if planting in pots. just dig a hole and drop the pot into it. If you find your plant topping out and getting bigger than surrounding vegetation then just lift pot out and dig hole deeper instead of bending stems etc.
Some northern growers would never see there ground temps rise enough to get a germ, thats why with a direct sow, and a germ at home you can get off to a start that is right for your environment.... What good would a August germ be if waiting for ground temps to hit 60-70? I personally have seen frost in the ground in May...@45N.
Now staying on track of the thread and initial question wannabe said he is in love with the MI5... So we know he wants to grow an auto, so if you want that auto done in time sow/germ accordingly...
I would also recommend a container grow or even a swamp tube... swamp tubes produce, far more than ground holes and are rarely ever found. Plus the sowing in a container/tube lessens the chance for critter attacks.