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 earliest that you can plant watermelon in Harrisburg can be determined by looking at 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 must 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 fully mature. Starting your watermelon indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Harrisburg. It might get as low as 5°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Harrisburg and it is different every year. Since half of the time in Harrisburg there is a last frost after April 15 be ready to protect your watermelon in the event of a surprise late frost.

USDA Zone Info for Harrisburg

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Harrisburg

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