When can I plant Lobelia in Zone 5a

One of the first steps we take when we are getting a good idea our gardening schedule is find our USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for our area.

A common way of figuring out when it's possible to plant lobelia is to examine the USDA zone info for Zone 5a.


Planting Calendar for Lobelia

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

You can plant lobelia a lot earlier in the year because they are very cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant lobelia
Possibly ok, but a risky time to plant lobelia
Probably not a good time to plant lobelia

The earliest that you can plant lobelia in Zone 5a 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. If you wait any later than that and your lobelia may not have a chance to grow to maturity. Starting your lobelia indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Zone 5a. It might get as low as -20°F during the coldest months of winter.

It's important to remember that our actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 5a and it can change quite a bit from year to year. Since half of the time in Zone 5a it frosts late in the year after April 15 be ready to cover your lobelia in the event of a surprise late frost.

USDA Zone Info for Zone 5a

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-20°F
Highest Expected Low-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Zone 5a

You may be interested in our other planting guides for Zone 5a.