One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. 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 Caldwell should be reviewed to figure out when to plant purple coneflower.

Planting Calendar for Purple Coneflower

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

Purple Coneflower do ok in moderate cold which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant purple coneflower in Caldwell 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 purple coneflower and expect a good harvest is probably August. You probably don't want to wait any later than that or else your purple coneflower may not have a chance to grow to maturity. If you are starting your purple coneflower indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Caldwell. In the coldest months of winter you can expect an average low temperature of -5°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Caldwell and it changes from year to year. Half of the time in Caldwell there is a last frost after April 15 so be sure to be ready to protect your purple coneflower if you have a late frost.

USDA Zone Info for Caldwell

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Caldwell

You may be interested in your other planting guides for Caldwell.