One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant watermelon in Harrisburg should be determined by reviewing the USDA zone info.

Planting Calendar for Watermelon

Frost tolerance for watermelon:	Not tolerant of frost.
When to plant:	After the last frost.

Watermelon are not cold tolerant which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant watermelon in Harrisburg is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant watermelon and expect a good harvest is probably August. You probably don't want to wait any later than that or else your watermelon may not have a chance to grow to maturity. You can get started a little bit earlier by starting your watermelon indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Harrisburg. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Harrisburg is not always accurate the actual date of last frost changes from year to year. Half of the time in Harrisburg you get surprised by a frost after April 15 so make sure that you are prepared to protect your watermelon in the event of a surprise late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Harrisburg

You may be interested in your other planting guides for Harrisburg.