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.

By using the USDA zone info for Herrin it's a good idea to determine when it's the best time to plant twinspur.

Planting Calendar for Twinspur

Frost tolerance for twinspur:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Twinspur do ok in some cold which means that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant twinspur 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 twinspur and expect a good harvest is probably September. You probably don't want to wait any later than that or else your twinspur may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your twinspur indoors.

Last Frost Date

The average date of last frost is April 15 in Herrin. In the coldest months of winter you can expect an average low temperature of -5°F.

Keep in mind that USDA zone info for Herrin is just an average and the actual date of last frost will vary from year to year. Since half of the time in Herrin last frost occurs after April 15 be ready to protect your twinspur in the event of one of those late frosts.

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.