One of the best tools that you have as gardeners to help us figure out 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.

The USDA zone info for Mill Valley should be used to determine when to plant nierembergia.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant nierembergia until after the last frost because they are not cold tolerant.

The earliest that you can plant nierembergia in Mill Valley 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 nierembergia and expect a good harvest is probably September. Any later than that and your nierembergia may not have a chance to really do well. Starting your nierembergia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is January 31 in Mill Valley. In the coldest months of winter you should expect an average low temperature of 30°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Mill Valley and it can change quite a bit from year to year. Half of the time in Mill Valley you get a frost after January 31 so always be ready to protect your nierembergia in the event of a late frost.

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.