How long weed stays in your system, this depends on the method of sampling. After you last took the drug, weed can be detected in your blood for a day or two days, your saliva for 2 to 3 days, urine for anywhere between 3 to 30 days, and hair follicles for up to 90 days. 

Depending on the amount you've consumed and how often you generally take the drug, these figures can vary.