I buy hot peppers and grow them but they are bitter. how do I grow spicy peppers?

Answer 1

You're picking them too early. Wait until the pepper changes color. In the case of green hot peppers like jalapenos, wait until they turn from bright green to a darker green.

Answer 2

Does any of your other produce (ie lettuce or carrots) have a bitter flavor? Different soil conditions produce different flavors. A good sterile steer manure gives a sweeter flavor than say chicken manure etc.
One of the best (cheapest)things I've found for adding flavor and growth to peppers is a little bit of Epsom Salt (magnesium sulfate)mixed in the soil at transplant. About 1/4 tsp per hole well mixed in the dirt.

Answer 3

Adding to Bradymsu's advice, be sure that you purchase quality plants to start with. You want them sort of small, with no blossoms on them before you transplant into your own garden. It reduces transplant shock, and you should get better yields.