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.

In Portsmouth you can determine when it's the best time to plant lobelia by using the USDA zone info.

Planting Calendar for Lobelia

Frost tolerance for lobelia:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since lobelia do well in cold you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant lobelia 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 lobelia and expect a good harvest is probably September. Any later than that and your lobelia may not have a chance to fully mature. Starting your lobelia indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Portsmouth the average date of last frost happens on March 15. 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 an average and the actual date of last frost is different every year. Since half of the time in Portsmouth there is a last frost after March 15 be ready to cover your lobelia if you have a 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.