Very Much in need of help.

Well guys ive decided best way to grow right now is to do some guerilla farming. And I need advice. I live in Northern Cali. its getting to be about 90 right now during the day. The soil here is shit. Its mostly clay. i was planning on a grow box where id make it about 6-8 inches tall. to put some good soil in it. i need to know what materials i need for a guerilla style grow. and also if its gonna be too hot to grow. Thank you.

what i did was dig holes in areas with taller weeds and filled it in with black dirt, and also im not sur ebut i dont think thats too hot