The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 Grinnell can be reviewed to determine when it's possible to plant perilla.

Planting Calendar for Perilla

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

You really shouldn't plant perilla until after the last frost because they do not do well in cold weather.

The earliest that you can plant perilla in Grinnell 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 perilla and expect a good harvest is probably August. Any later than that and your perilla may not have a chance to really do well. Starting your perilla indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Grinnell. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Grinnell is just an average the actual date of last frost is different every year. Half of the time in Grinnell you get a frost after April 15 so make sure that you are prepared to protect your perilla in the event of a surprise late frost.

USDA Zone Info for Grinnell

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Grinnell

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