What effect did Eli Whitney's cotton gin have on the Southern economy?

The cotton gin impacted the South’s economy by improving it, but also by making it depend more on cotton and therefore on slavery.

Before Eli Whitney invented the cotton gin, cotton was not a very big crop in the United States.  It was simply too hard to get the seeds out of the cotton.  Therefore, it was not widely grown.  Whitney’s cotton gin changed this by making it rather easy to remove seeds from the cotton.  According to the link below, the US produced only 1500 pounds of cotton in 1790.  By 1800, the country was producing 35,000 pounds per year.  By 1815, the number 100,000 pounds and production actually exceeded 1 million pounds in 1848.  According to this link, the US produced almost four times as much cotton in 1860 as it had in 1830.

What this shows is that cotton boomed after Eli Whitney invented the cotton gin.  This improved the Southern economy because it created this huge cash crop that became the basis of the South’s economy.  Less happily, it also caused the South to base its entire economy on slavery.  Cotton in those days could not be grown without slave labor.  If the South needed cotton, that meant that it also needed slaves.  In these ways, the cotton gin impacted the South’s economy by giving it a new cash crop, but it also made the South depend on slavery for its economic prosperity.