Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Rapid City should be looked at to estimate when to plant lobelia.

Planting Calendar for Lobelia

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

Since lobelia are very cold tolerant you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant lobelia in Rapid City 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

In Rapid City the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that USDA zone info for Rapid City is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Rapid City it frosts late in the year after April 15 be ready to protect your lobelia if you have a late frost.

USDA Zone Info for Rapid City

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 Rapid City

You may be interested in your other planting guides for Rapid City.