One of the first steps you take when you are estimating 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.

By checking out the USDA zone info for Mill Valley it's a good idea to estimate when it's a good idea to plant sweet williams.

Planting Calendar for Sweet Williams

Frost tolerance for sweet williams:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Sweet Williams tend to make it in some cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant sweet williams in Mill Valley is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant sweet williams and expect a good harvest is probably October. You probably don't want to wait any later than that or else your sweet williams may not have a chance to really do well. You can get started a few weeks earlier by starting your sweet williams indoors.

Last Frost Date

On average all chance of frost has passed is on January 31 in Mill Valley. You should expect an average low temperature of 30°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Mill Valley is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Mill Valley last frost occurs after January 31 so make sure that you are prepared to cover your sweet williams in the event of one of those late frosts.

USDA Zone Info for Mill Valley

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 Mill Valley

You may be interested in your other planting guides for Mill Valley.