One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant watermelon in Thornton can be figured out by using the USDA zone info.

Planting Calendar for Watermelon

Frost tolerance for watermelon:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

You should not plant watermelon until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant watermelon in Thornton 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. Any later than that and your watermelon may not have a chance to really do well. You can get started a little bit earlier by starting your watermelon indoors.

Last Frost Date

On average the last frost is on April 15 in Thornton. You can expect an average low temperature of -15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Thornton and it can change quite a bit from year to year. Since half of the time in Thornton there is a last frost after April 15 be ready to cover your watermelon if you have a late frost.

USDA Zone Info for Thornton

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 Thornton

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