The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. 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 figure out when it's possible to plant bidens by referring to the USDA zone info for Olympia.

Planting Calendar for Bidens

Frost tolerance for bidens:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since bidens are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant bidens in Olympia is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant bidens and expect a good harvest is probably August. Any later than that and your bidens may not have a chance to really do well. Starting your bidens indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Olympia. In the coldest months of winter you should expect an average low temperature of 10°F.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Olympia and it changes from year to year. Half of the time in Olympia it frosts late in the year after March 15 so be sure to be ready to protect your bidens in the event of a surprise late frost.

USDA Zone Info for Olympia

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 Olympia

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