The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Merced can be reffered to in order to figure out when to plant periwinkles.

Planting Calendar for Periwinkles

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

Since periwinkles require warm weather 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 Merced 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 really do well. Starting your periwinkles indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Merced. It might get as low as 20°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Merced and it will vary from year to year. Since half of the time in Merced it frosts late in the year after February 15 be ready to cover your periwinkles if you have one of those late frosts.

USDA Zone Info for Merced

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Merced

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