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.

The USDA zone info for Galveston can be reffered to in order to estimate when it's a good idea to plant periwinkles.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's a bad idea to plant periwinkles until after the last frost because they are not cold tolerant.

The earliest that you can plant periwinkles in Galveston 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 periwinkles and expect a good harvest is probably September. If you wait any later than that and your periwinkles may not have a chance to fully mature. If you are starting your periwinkles indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Galveston the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 25°F.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Galveston and it changes from year to year. Half of the time in Galveston you get a frost after February 15 so just be sure to be ready to protect your periwinkles in the event of a late frost.

USDA Zone Info for Galveston

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 Galveston

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