One of my friends enlisted in the Marines a while back. He failed the piss test in basic training but it took them one month to kick him out. He wasted a month of his life and had to wait two years to re-enlist. And if you are applying for any branch besides the Marines, you can forget about joining the military at all. The other branches won't give you a second chance.

I strongly recommend delaying your ship date by whatever means necessary. It hasn't been too long since you last smoked and the military drug tests have a low threshold for THC. Dilution or subbing will not be available to save you. I would not take the risk.

If you fail the test, you'll look like a fool. Imagine having to explain to everyone you know why you got kicked out of basic training. As a last resort if you can't think of any creative lies, you can explain your situation to your recruiter. He'll probably IT the piss out of you but he'll understand and help you out.

But it's your life. It's up to you. Good luck in whatever you choose.