One of the first steps you take when you are determining your gardening schedule is find your 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 Harlingen you can estimate when to plant four o' clock by looking at the USDA zone info.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since four o' clock require warm weather you must wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant four o' clock in Harlingen is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant four o' clock and expect a good harvest is probably September. If you wait any later than that and your four o' clock may not have a chance to fully mature. You can get started a few weeks earlier by starting your four o' clock indoors.

Last Frost Date

On average the last frost has passed is on February 15 in Harlingen. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Harlingen is not always accurate the actual date of last frost will vary from year to year. Half of the time in Harlingen last frost occurs after February 15 so just be sure to be ready to protect your four o' clock if you have a surprise late frost.

USDA Zone Info for Harlingen

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Harlingen

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