Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when it's a good idea to plant napa valley fern in Alton by referring to the USDA zone info.

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.

It's not a good idea to plant napa valley fern until after the last frost because they are not cold tolerant.

The earliest that you can plant napa valley fern in Alton 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. 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. Starting your napa valley fern indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Alton. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Alton is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Alton you get a frost after April 15 be ready to cover your napa valley fern in the event of a late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Alton

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