What does it mean? How can wind increase the growth of nut grass?

‘Why,one sprig of nut-grass can ruin a whole yard.Look here.When it comes fall this dries up and the wind blows it all over Maycomb County!’ To kill a mockingbird ( chapter 5)
Answers

Stella

The wind blows the seeds around, causing it to spread.

j

The subtext is "one bad apple," as in one false claim of #metoo (re Robinson) is blown about Maycomb County by the winds of gossip.

They Pelted Us With Rocks And Garbage

Wind blows the seed.