The USDA Zone info is a great tool for gardeners to help us determine 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.

One way of getting a good idea when you can plant perilla is to use the USDA zone info for Harvard.

Planting Calendar for Perilla

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

Perilla require warm weather which tells us that it is 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 perilla in Harvard 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. If you wait any later than that and your perilla may not have a chance to grow to maturity. If you are starting your perilla indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Harvard the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that USDA zone info for Harvard is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Harvard there is a last frost after April 15 be ready to protect your perilla in the event of a late frost.

USDA Zone Info for Harvard

Here is the info for USDA Zone 5b.

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

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

Plants to Grow in Harvard

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