One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when to plant nierembergia by reviewing the USDA zone info for Roseville.

Planting Calendar for Nierembergia

Frost tolerance for nierembergia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Nierembergia do not do well in cold weather which means that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant nierembergia in Roseville 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. If you wait any later than that and your nierembergia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your nierembergia indoors.

Last Frost Date

On average the last frost is on February 15 in Roseville. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Roseville is just an average the actual date of last frost is different every year. Since half of the time in Roseville you get surprised by a frost after February 15 be ready to cover your nierembergia in the event of one of those late frosts.

USDA Zone Info for Roseville

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 Roseville

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