First time planting in pots, most other veggies are doing well. Balls bush Zuc. planted 1 1/2 mo. ago in a large pot. The pot is 16" across at the top and 16" tall. I filled with Amend and used an organic fertilizer, 4-6-3.It is a single plant due to space constraints. Plant was doing well but started yellowing about 3 weeks ago, as did the other summer squash. I live in a hot area in Ca. and at first I was watering twice a day because the soil was drying out so fast and they were a bit wilted at the end of the day. I gradually cut them back to once a day as they took hold and took off. I usually watered until the it came out the bottom. 3 weeks ago when I noticed the yellowing I cut back more on the watering. Once a day with out water coming out the bottom as long a the plants weren't wilting,looking well and soil was semi damp. I added more fertilizer as I figured the over watering had leached out the soil. All of the squash greened up and were growing even better, they are all now setting flowers and veggies. The Zuc, however, isn't doing as well. Its leaves are nice and green now and it's setting more veggies and flowers but the vegy itself starts out green and wonderful, then starts to yellow out at then end and gradually spreads to the thing. I see no blossom end rot or any other pest/disease. When this happens, it is about 1/2 a finger, or so, in length and robust and the flower has already dried up and fallen off. I was wondering if watering it once a day is still too much and they need more nitrogen again, or if they aren't being pollinated, if they are over fertilized. I've never had this problem before when I planted straight in the ground. I'm not sure how the other squash are going to do once they start setting fruit, they are all flowering now. Tomatoes, beans, etc. are all doing great.