One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's the best time to plant bidens by referring to the USDA zone info for Columbia.

Planting Calendar for Bidens

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

Bidens do not do well in cold weather which tells us that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant bidens in Columbia 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 fully mature. Starting your bidens indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Columbia is not always accurate the actual date of last frost is different every year. Half of the time in Columbia you get a frost after March 15 so make sure that you are ready to cover your bidens if you have a late frost.

USDA Zone Info for Columbia

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 Columbia

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