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.

By reviewing the USDA zone info for Half Moon Bay you should be able to figure out when it's possible to plant periwinkles.

Planting Calendar for Periwinkles

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

Since periwinkles are not cold tolerant it's important to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant periwinkles in Half Moon Bay 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. You probably don't want to wait any later than that or else your periwinkles may not have a chance to grow to maturity. If you are starting your periwinkles indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Half Moon Bay the average date of last frost happens on January 31. You can expect an average low temperature of 30°F in the coldest months of winter.

It's important to remember that USDA zone info for Half Moon Bay is just an average and the actual date of last frost is different every year. Half of the time in Half Moon Bay you get surprised by a frost after January 31 so make sure that you are ready to protect your periwinkles if you have a surprise late frost.

USDA Zone Info for Half Moon Bay

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 Half Moon Bay

You may be interested in your other planting guides for Half Moon Bay.