One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of making a decision about when it's a good idea to plant petunias is to refer to the USDA zone info for Westminster.

Planting Calendar for Petunias

Frost tolerance for petunias:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant petunias just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant petunias in Westminster 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 petunias and expect a good harvest is probably September. Any later than that and your petunias may not have a chance to fully mature. You can get started a few weeks earlier by starting your petunias indoors.

Last Frost Date

On average all chance of frost has passed is on January 31 in Westminster. It might get as low as 35°F during the coldest months of winter.

Since the USDA zone info for Westminster is an average the actual date of last frost will vary from year to year. Since half of the time in Westminster you get a frost after January 31 be ready to cover your petunias in the event of a surprise late frost.

USDA Zone Info for Westminster

Here is the info for USDA Zone 10b.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	35°F
Highest Expected Low	40°F

This means that on a really cold year, the coldest it will get is 35°F. On most years you should be prepared to experience lows near 40°F.

Plants to Grow in Westminster

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