Before planting it is a good idea to find your USDA Zone info to figure out 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 Zone 5a should be looked at to estimate when it's a good idea to plant bidens.

Planting Calendar for Bidens

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

You can not plant bidens until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant bidens in Zone 5a 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 grow to maturity. If you are starting your bidens indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Zone 5a the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 5a is an average and the actual date of last frost changes from year to year. Half of the time in Zone 5a it frosts late in the year after April 15 so make sure that you are prepared to cover your bidens in the event of a surprise late frost.

USDA Zone Info for Zone 5a

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

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

Plants to Grow in Zone 5a

You may be interested in your other planting guides for Zone 5a.