Before planting it is a good idea to find your USDA Zone info to estimate 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 Glen Carbon should be reffered to in order to determine when it's a good idea to plant helianthemum.

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 Glen Carbon 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. If you wait any later than that and your helianthemum may not have a chance to grow to maturity. Starting your helianthemum indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Glen Carbon the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

Always keep in mind that USDA zone info for Glen Carbon may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Glen Carbon there is a last frost after April 15 be ready to protect your helianthemum if you have a surprise late frost.

USDA Zone Info for Glen Carbon

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 Glen Carbon

You may be interested in your other planting guides for Glen Carbon.