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.

A way of making a decision about when it's the best time to plant lobelia is to consult the USDA zone info for Portsmouth.

Planting Calendar for Lobelia

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

Lobelia do well in cold which means that you can start planting them much earlier than other frost tender plants.

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. You probably don't want to wait any later than that or else your lobelia may not have a chance to really do well. 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 April 15. In the coldest months of winter you should expect an average low temperature of -5°F.

Since the USDA zone info for Portsmouth may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Portsmouth last frost occurs after April 15 be ready to protect your lobelia in the event of one of those late frosts.

USDA Zone Info for Portsmouth

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 Portsmouth

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