I've had several vegetables die off due to "pinched" stems. It looked as if someone had pinched the main stem at ground level. The upper stem looks fine but soon after the plant dies. I've seen this happen with my Alstroemeria too and it had 2 pinched sections. One area was above ground level several inches and the other pinched area was at ground level. Is this a bug? Something to do with watering? it's a mystery to me... Randy