I have a drug test (urine) for the plants in 3 weeks i roll joints for my friends and accidentally licked my fingers will i fail?

Depends: Are you exposed to the smoke from your friends? Second hand smoke is more likely to make you fail the test than licking your fingers. If you avoid any and all exposure to weed for the next three weeks, you should be okay. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.