It needed some basic ferts...goto a walgreens,walmart, riteaid etc.. and get some schultz liquid plant food its like 7 drops per quart of water. That well help the yellowing and also make sure you flush or just give it water for the last coupel weeks. Even on cloudy day you still UV rays coming down just not as well as clear. Give it a couple weeks from seed before any nutes and just half or quarter strength the first once or twice as not to burn them.