Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Colusa should be looked at to determine when you can plant nierembergia.

Planting Calendar for Nierembergia

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

Since nierembergia require warm weather you really should wait until after the last frost before you can plant them.

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

Last Frost Date

On average the last frost has passed is on February 15 in Colusa. You should expect an average low temperature of 25°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Colusa is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Colusa you get surprised by a frost after February 15 so make sure that you are ready to protect your nierembergia in the event of a late frost.

USDA Zone Info for Colusa

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 Colusa

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