One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 Helena should be looked at to figure out when it's the best time to 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 has passed.

You really shouldn't plant napa valley fern until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant napa valley fern in Helena is April. However, you really should wait until May 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. Any later than that and your napa valley fern may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your napa valley fern indoors.

Last Frost Date

The average date of last frost is March 15 in Helena. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Helena last frost occurs after March 15 so be sure to be ready to protect your napa valley fern in the event of a surprise late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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