Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when to plant watermelon by looking at the USDA zone info for Denver.

Planting Calendar for Watermelon

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

Watermelon require warm weather which means that it is important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant watermelon in Denver 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. Starting your watermelon indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Denver. It might get as low as -15°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Denver and it is different every year. Since half of the time in Denver you get surprised by a frost after April 15 be ready to cover your watermelon in the event of one of those late frosts.

USDA Zone Info for Denver

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Denver

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