Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. 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 Grass Valley should be read to figure out when you can plant four-o-clock flower.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since four-o-clock flower do not do well in cold weather it is necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant four-o-clock flower in Grass Valley 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 four-o-clock flower and expect a good harvest is probably September. If you wait any later than that and your four-o-clock flower may not have a chance to really do well. If you are starting your four-o-clock flower indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Grass Valley. It might get as low as 20°F during the coldest months of winter.

Since the USDA zone info for Grass Valley is an average the actual date of last frost will vary from year to year. Since half of the time in Grass Valley last frost occurs after February 15 be ready to protect your four-o-clock flower if you have a late frost.

USDA Zone Info for Grass Valley

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Grass Valley

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