I grow in mostly clay and my holes are 3' wide and about 15-18" deep. I would recommend planting a winter/spring cover crop in your native soil if your clay soil drains poorly, then mulch the native soil with woodchips once the growing season starts. After a few years you should have good soil...
I should clarify that I was talking about strains with purple in name. I had a blue widow that turned purple from cold outdoor weather that was very potent. I'm also a fan of the forum cut gsc.
My personal experience with anything purple has been terrible. 99% of purple strains I have smoked were very weak, some were like smoking hemp. It has turned me off after so many disappointing experiences.
Most plants bloom somewhere between 14 - 14.50 hours daylight.I bloom clones at 14.25 hours daylight (14 hours and 15 minutes). Anything that blooms at 14.25 will start blooming late July/early August and finish usually around early October or earlier. I definitely suggest people give it a try...