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.

The USDA zone info for Helena can be reffered to in order to determine when it's the best time to plant stoneseed.

Planting Calendar for Stoneseed

Frost tolerance for stoneseed:	Not tolerant of frost.
When to plant:	After the last frost.

You really shouldn't plant stoneseed until after the last frost because they are not cold tolerant.

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

Last Frost Date

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

Keep in mind that USDA zone info for Helena may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Helena last frost occurs after May 15 be ready to cover your stoneseed 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.