One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant tithonia in Great Falls can be figured out by reviewing the USDA zone info.

Planting Calendar for Tithonia

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

Since tithonia do not do well in cold weather it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant tithonia in Great Falls 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 tithonia and expect a good harvest is probably August. If you wait any later than that and your tithonia may not have a chance to fully mature. If you are starting your tithonia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Great Falls. In the coldest months of winter you can expect an average low temperature of -30°F.

Always keep in mind 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 Great Falls and it is different every year. Half of the time in Great Falls it frosts late in the year after May 15 so be sure to be ready to protect your tithonia if you have a surprise late frost.

USDA Zone Info for Great Falls

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Great Falls

You may be interested in your other planting guides for Great Falls.