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.

In Kelso you can figure out when to plant bidens by referring to the USDA zone info.

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 have to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant bidens in Kelso 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. You probably don't want to wait any later than that or else your bidens may not have a chance to grow to maturity. If you are starting your bidens indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Kelso is an average the actual date of last frost changes from year to year. Half of the time in Kelso last frost occurs after March 15 so always be ready to protect your bidens in the event of a late frost.

USDA Zone Info for Kelso

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Kelso

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