One of the best tools that you have as gardeners to help us determine 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 Hayward you can estimate when it's the best time to plant periwinkles by reviewing the USDA zone info.

Planting Calendar for Periwinkles

Frost tolerance for periwinkles:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Periwinkles are not cold tolerant which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant periwinkles in Hayward is February. However, you really should wait until March 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. Any later than that and your periwinkles may not have a chance to fully mature. Starting your periwinkles indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on January 31 in Hayward. You can expect an average low temperature of 30°F in the coldest months of winter.

Keep in mind that USDA zone info for Hayward is an average and the actual date of last frost is different every year. Since half of the time in Hayward you get surprised by a frost after January 31 be ready to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for Hayward

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Hayward

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