One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's a good idea to plant helianthemum in Chehalis by referring to the USDA zone info.

Planting Calendar for Helianthemum

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

Helianthemum can survive in mild cold which means that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant helianthemum in Chehalis 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. Any later than that and your helianthemum may not have a chance to fully mature. If you are starting your helianthemum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Chehalis the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

It's important to remember that USDA zone info for Chehalis is just an average and the actual date of last frost changes from year to year. Since half of the time in Chehalis you get a frost after March 15 be ready to cover your helianthemum in the event of a late frost.

USDA Zone Info for Chehalis

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Chehalis

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