One of the first steps you take when you are estimating 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.

In Lewistown you can determine when it's possible to plant heliotrope by reviewing the USDA zone info.

Planting Calendar for Heliotrope

Frost tolerance for heliotrope:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant heliotrope until after the last frost has passed because they require warm weather.

The earliest that you can plant heliotrope in Lewistown 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 heliotrope and expect a good harvest is probably August. You probably don't want to wait any later than that or else your heliotrope may not have a chance to grow to maturity. If you are starting your heliotrope 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 is on May 15 in Lewistown. In the coldest months of winter you should expect an average low temperature of -30°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Lewistown and it can change quite a bit from year to year. Since half of the time in Lewistown it frosts late in the year after May 15 be ready to protect your heliotrope in the event of one of those late frosts.

USDA Zone Info for Lewistown

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 Lewistown

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