The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant periwinkles in San Luis Obispo can be figured out by referring to 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.

You really shouldn't plant periwinkles until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant periwinkles in San Luis Obispo 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. You probably don't want to wait any later than that or else your periwinkles may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your periwinkles indoors.

Last Frost Date

The average date of last frost is February 15 in San Luis Obispo. In the coldest months of winter you can expect an average low temperature of 25°F.

Since the USDA zone info for San Luis Obispo is an average the actual date of last frost can change quite a bit from year to year. Half of the time in San Luis Obispo you get surprised by a frost after February 15 so be sure to be ready to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.