The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant lobelia in Castle Rock can be figured out by referring to 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 quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant lobelia in Castle Rock 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 really do well. You can get started a little bit earlier by starting your lobelia indoors.

Last Frost Date

In Castle Rock the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Castle Rock is not always accurate the actual date of last frost will vary from year to year. Half of the time in Castle Rock you get surprised by a frost after April 15 so make sure that you are prepared to cover your lobelia in the event of a surprise late frost.

USDA Zone Info for Castle Rock

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Castle Rock

You may be interested in your other planting guides for Castle Rock.