Before planting it is a good idea to find your USDA Zone info to determine 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.

In Zone 1a you can estimate when it's a good idea to plant bidens by checking out 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.

Bidens do not do well in cold weather which tells us that it's important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant bidens in Zone 1a is June. However, you really should wait until July if you don't want to take any chances.

The last month that you can plant bidens and expect a good harvest is probably July. If you wait any later than that and your bidens may not have a chance to grow to maturity. Starting your bidens indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Zone 1a the average date of last frost happens on June 15. You should expect an average low temperature of -60°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 1a and it can change quite a bit from year to year. Half of the time in Zone 1a you get surprised by a frost after June 15 so make sure that you are prepared to protect your bidens if you have a late frost.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-60°F
Highest Expected Low	-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.