One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. 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 Riverside can be read to figure out when you can plant pentas.

Planting Calendar for Pentas

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

It's probably a bad idea to plant pentas until after all chance of frost has passed because they require warm weather.

The earliest that you can plant pentas in Riverside 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 pentas and expect a good harvest is probably September. If you wait any later than that and your pentas may not have a chance to really do well. If you are starting your pentas indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Riverside. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Riverside is not always accurate the actual date of last frost is different every year. Half of the time in Riverside it frosts late in the year after February 15 so make sure that you are prepared to cover your pentas if you have one of those late frosts.

USDA Zone Info for Riverside

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 Riverside

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