One of the best tools that you have as gardeners to help us estimate 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.

In Riverside you can determine when it's a good idea to plant watermelon 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 when the weather gets warmer.

Since watermelon require warm weather you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant watermelon in Riverside 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 grow to maturity. You can get started a little bit earlier by starting your watermelon indoors.

Last Frost Date

In Riverside the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that USDA zone info for Riverside is an average and the actual date of last frost is different every year. Half of the time in Riverside you get a frost after April 15 so make sure that you are prepared to cover your watermelon in the event of a late frost.

USDA Zone Info for Riverside

Here is the info for USDA Zone 6a.

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

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Riverside

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