One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Marengo should be reviewed to figure out when it's possible to plant thyme.

Planting Calendar for Thyme

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

Thyme do well in cold which means that you can start planting them much earlier than other frost tender plants.

The earliest that you can plant thyme in Marengo 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 thyme and expect a good harvest is probably September. You probably don't want to wait any later than that or else your thyme may not have a chance to fully mature. If you are starting your thyme indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Marengo. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Marengo is just an average the actual date of last frost will vary from year to year. Since half of the time in Marengo last frost occurs after April 15 be ready to cover your thyme if you have a late frost.

USDA Zone Info for Marengo

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 Marengo

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