The other factor is the heat. We have seen numerous 98deg days here. This temp is not good for our spring crops. They've shown signs of stress. My tater tires are showing stress as well. Could be tater blight or just could be the weather affecting them.
I noticed that the tater tire stacked two high looked bad for a bit and I stopped watering it. It looks much better and has begun to flower. Its catching up to the other two I planted round 2 weeks later. The difference is I kept if from growing by adding dirt and another tire to see what kind of harvest I might get. Here's a pick of the overall garden with the four test tater plants. Two in tires of differing height and two in the ground.
We're hoping for a harvest but we'll have to see. Really wanting to get a crop this year. If nothing else and the taters aren't affected with tater blight then we may get a good crop of them.