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

You can estimate when you can plant napa valley fern in Zone 4b by checking out the USDA zone info.

Planting Calendar for Napa Valley Fern

Frost tolerance for napa valley fern:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Napa Valley Fern are not cold tolerant which means that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant napa valley fern in Zone 4b is May. However, you really should wait until June 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 August. You probably don't want to wait any later than that or else your napa valley fern may not have a chance to really do well. If you are starting your napa valley fern 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 May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

It's important to remember that USDA zone info for Zone 4b is an average and the actual date of last frost will vary from year to year. Since half of the time in Zone 4b last frost occurs after May 15 be ready to cover your napa valley fern if you have a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.