One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

You should be able to determine when you can plant helianthemum by looking at the USDA zone info for Rittman.

Planting Calendar for Helianthemum

Frost tolerance for helianthemum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since helianthemum are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant helianthemum in Rittman is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant helianthemum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your helianthemum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your helianthemum indoors.

Last Frost Date

In Rittman the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Just be sure to remember that USDA zone info for Rittman is an average and the actual date of last frost is different every year. Half of the time in Rittman there is a last frost after April 15 so just be sure to be ready to cover your helianthemum if you have a late frost.

USDA Zone Info for Rittman

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Rittman

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