Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 possible to plant columbine by reviewing the USDA zone info for Portsmouth.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Columbine can survive in moderate cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant columbine in Portsmouth is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant columbine and expect a good harvest is probably September. You probably don't want to wait any later than that or else your columbine may not have a chance to grow to maturity. You can get started a little bit earlier by starting your columbine indoors.

Last Frost Date

The average date of last frost is March 15 in Portsmouth. It might get as low as 10°F during the coldest months of winter.

Always keep in mind that USDA zone info for Portsmouth is not always accurate and the actual date of last frost is different every year. Half of the time in Portsmouth there is a last frost after March 15 so make sure that you are ready to cover your columbine if you have a surprise late frost.

USDA Zone Info for Portsmouth

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 Portsmouth

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