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.

One way of estimating when it's a good idea to plant napa valley fern is to consult the USDA zone info for Crookston.

Planting Calendar for Napa Valley Fern

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

It's probably not a good idea to plant napa valley fern until after all chance of frost has passed because they require warm weather.

The earliest that you can plant napa valley fern in Crookston 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. If you wait any later than that and your napa valley fern may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your napa valley fern indoors.

Last Frost Date

The average date of last frost is May 15 in Crookston. It might get as low as -30°F during the coldest months of winter.

It's important to remember that USDA zone info for Crookston is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Crookston last frost occurs after May 15 be ready to protect your napa valley fern in the event of one of those late frosts.

USDA Zone Info for Crookston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°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 -25°F.

Plants to Grow in Crookston

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