Before planting it is a good idea to find your USDA Zone info to estimate 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 Thornton can be reviewed to estimate when it's possible to plant black eyed susans.

Planting Calendar for Black Eyed Susans

Frost tolerance for black eyed susans:	Not tolerant of frost.
When to plant:	After the last frost.

Black Eyed Susans do not do well in cold weather which tells us that it is necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant black eyed susans in Thornton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant black eyed susans and expect a good harvest is probably August. Any later than that and your black eyed susans may not have a chance to grow to maturity. Starting your black eyed susans indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Thornton 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.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Thornton and it changes from year to year. Half of the time in Thornton it frosts late in the year after April 15 so make sure that you are prepared to cover your black eyed susans in the event of a late frost.

USDA Zone Info for Thornton

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 Thornton

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