One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of estimating when it's possible to plant sanvitalia is to use the USDA zone info for Helena.

Planting Calendar for Sanvitalia

Frost tolerance for sanvitalia:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant sanvitalia just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant sanvitalia 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 sanvitalia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sanvitalia may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your sanvitalia indoors.

Last Frost Date

In Helena the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Helena it frosts late in the year after March 15 so be sure to be ready to cover your sanvitalia if you have a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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