The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

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

Planting Calendar for Bidens

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

It's probably not a good idea to plant bidens until after the last frost has passed because they require warm weather.

The earliest that you can plant bidens in Somerville 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. 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 April 15 in Somerville. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Somerville is not always accurate the actual date of last frost is different every year. Since half of the time in Somerville there is a last frost after April 15 be ready to cover your bidens in the event of a surprise late frost.

USDA Zone Info for Somerville

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Somerville

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