The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Flagstaff can be looked at to figure out when you can plant portulaca.

Planting Calendar for Portulaca

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

Since portulaca require warm weather it is important to wait until after the last frost has passed before you can plant them.

The earliest that you can plant portulaca in Flagstaff 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 portulaca and expect a good harvest is probably August. If you wait any later than that and your portulaca may not have a chance to really do well. Starting your portulaca indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Flagstaff. You can expect an average low temperature of -10°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Flagstaff and it will vary from year to year. Since half of the time in Flagstaff you get surprised by a frost after April 15 be ready to protect your portulaca if you have a surprise late frost.

USDA Zone Info for Flagstaff

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 Flagstaff

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