One of the best tools that you have as gardeners to help us determine 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.

By using the USDA zone info for Riverside it's a good idea to determine when you can plant napa valley fern.

Planting Calendar for Napa Valley Fern

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

Since napa valley fern require warm weather you have to wait until after the last frost before you can plant them.

The earliest that you can plant napa valley fern 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 napa valley fern and expect a good harvest is probably September. Any later than that and your napa valley fern may not have a chance to really do well. Starting your napa valley fern indoors is a great way to get them started a little bit earlier.

Last Frost Date

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

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Riverside and it can change quite a bit from year to year. Since half of the time in Riverside you get surprised by a frost after February 15 be ready to cover your napa valley fern in the event of a surprise late frost.

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.