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.

You can figure out when it's a good idea to plant nicotiana in Helena by using the USDA zone info.

Planting Calendar for Nicotiana

Frost tolerance for nicotiana:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Nicotiana are not cold tolerant which tells us that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant nicotiana in Helena is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant nicotiana and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nicotiana may not have a chance to grow to maturity. If you are starting your nicotiana indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Helena and it can change quite a bit from year to year. Half of the time in Helena there is a last frost after May 15 so just be sure to be ready to protect your nicotiana if you have a surprise late frost.

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.