[VLM]

That's whats implied in the article, and it may be true, or a part of the truth, aside from that, from growing up with my gentleman farmer uncle, I know low K results in weak stems/leaves. This was often a problem with his popcorn field (yes there are specific breeds of corn for popcorn its not just generic corn, although he also grew sweetcorn for picnics and stuff... he was a popular guy) Those lettuce plants would probably blow flat if you breathed on them hard, much less put them out in the wind. I would predict low-K lettuce is significantly less crunchy that normal lettuce.