One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Rialto you can estimate when it's a good idea to plant missouri primrose by checking out the USDA zone info.

Planting Calendar for Missouri Primrose

Frost tolerance for missouri primrose:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since missouri primrose are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant missouri primrose in Rialto is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant missouri primrose and expect a good harvest is probably October. Any later than that and your missouri primrose may not have a chance to grow to maturity. If you are starting your missouri primrose indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is January 31 in Rialto. It might get as low as 30°F during the coldest months of winter.

Since the USDA zone info for Rialto is an average the actual date of last frost changes from year to year. Half of the time in Rialto it frosts late in the year after January 31 so just be sure to be ready to cover your missouri primrose if you have one of those late frosts.

USDA Zone Info for Rialto

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 Rialto

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