The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant strawflowers in Castle Rock can be estimated by checking out the USDA zone info.

Planting Calendar for Strawflowers

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

Strawflowers do well in a tiny bit of cold which tells us that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant strawflowers 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 strawflowers and expect a good harvest is probably August. Any later than that and your strawflowers may not have a chance to grow to maturity. If you are starting your strawflowers 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. You can expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Castle Rock and it can change quite a bit from year to year. Half of the time in Castle Rock you get a frost after April 15 so just be sure to be ready to cover your strawflowers if you have one of those late frosts.

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.