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 will be able to determine when it's a good idea to plant bidens by referring to the USDA zone info for Keene.

Planting Calendar for Bidens

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

Since bidens require warm weather you need 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 Keene 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 little bit earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Keene. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Keene is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Keene you get a frost after March 15 so be sure to be ready to protect your bidens if you have a surprise late frost.

USDA Zone Info for Keene

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 Keene

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