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.

By referring to the USDA zone info for Helena it's a good idea to figure out when it's the best time 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.

Since oregano are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant oregano in Helena 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. You probably don't want to wait any later than that or else your oregano may not have a chance to really do well. Starting your oregano indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Helena the average date of last frost happens on May 15. You should expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Helena is an average the actual date of last frost changes from year to year. Half of the time in Helena last frost occurs after May 15 so make sure that you are ready to cover your oregano if you have one of those late frosts.

USDA Zone Info for Helena

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 Helena

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