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

The USDA zone info for Zone 4b should be reviewed to determine when it's possible to plant oregano.

Planting Calendar for Oregano

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

Oregano are one of those plants that can tolerate a little bit of cold weather which means that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant oregano 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 oregano and expect a good harvest is probably August. If you wait any later than that and your oregano may not have a chance to fully mature. You can get started a few weeks earlier by starting your oregano indoors.

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 4b and it will vary from year to year. Half of the time in Zone 4b it frosts late in the year after May 15 so make sure that you are prepared to protect your oregano if you have a surprise 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.