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.

By checking out the USDA zone info for Zone 4b it's a good idea to estimate when it's a good idea 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 ok in pretty solid cold which tells us that you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant thyme in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant thyme and expect a good harvest is probably August. Any later than that and your thyme may not have a chance to grow to maturity. If you are starting your thyme indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4b is an average and the actual date of last frost changes from year to year. Half of the time in Zone 4b you get surprised by a frost after May 15 so make sure that you are prepared to protect your thyme if you have a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.