Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant tritoma in Herrin should be estimated by referring to the USDA zone info.

Planting Calendar for Tritoma

Frost tolerance for tritoma:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since tritoma are very cold tolerant you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant tritoma in Herrin is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant tritoma and expect a good harvest is probably September. You probably don't want to wait any later than that or else your tritoma may not have a chance to really do well. If you are starting your tritoma indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Herrin the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Herrin is just an average the actual date of last frost is different every year. Half of the time in Herrin you get surprised by a frost after April 15 so be sure to be ready to cover your tritoma in the event of a surprise late frost.

USDA Zone Info for Herrin

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Herrin

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