How do i gain 50 pounds by basketball season?

Pb&j is just not going to get it done. You should eat at least 3 LARGE meals consisting of MEAT and VEGETABLES. Use the pb&j as a snack. Snack about 2 or more times a day. And eat as much as u can at every meal. Eating fast food would be better then a pb&j as far as gaining weight. Also when u work out keep your weight high and reps low, and rest for a while between sets. And dont do the same muscle group more than 1 or 2 times a week. If you have the money try to get some protein powder or meal replacements and drink them 2 times a day. If you dont have the money for powder, try slimfast or a weigh loss drink like that but drink it with a meal. 50 pounds in far fetched but i wouldnt say it isnt possible at your age. I gained 50 pounds in about 2 months when i was in high school for football. good luck