The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of getting a good idea when it's a good idea to plant nierembergia is to refer to the USDA zone info for Mercedes.

Planting Calendar for Nierembergia

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

Since nierembergia do not do well in cold weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant nierembergia in Mercedes 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 fully mature. If you are starting your nierembergia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Mercedes the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Mercedes and it changes from year to year. Half of the time in Mercedes last frost occurs after February 15 so always be ready to cover your nierembergia if you have a surprise late frost.

USDA Zone Info for Mercedes

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 Mercedes

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