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.

In Castle Rock you can determine when it's a good idea to plant monarda by looking at the USDA zone info.

Planting Calendar for Monarda

Frost tolerance for monarda:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant monarda just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant monarda in Castle Rock is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant monarda and expect a good harvest is probably August. Any later than that and your monarda may not have a chance to really do well. If you are starting your monarda indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Castle Rock is not always accurate the actual date of last frost changes from year to year. Half of the time in Castle Rock there is a last frost after April 15 so always be ready to cover your monarda 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.